THE ROMANCE 
 OF MODERN 
 RAILWAYS 
 
 THOMAS 
 
 N 
 
THE ROMANCE 
 OF MODERN RAILWAYS 
 
By permission of] 
 
 The L. & N.W. Railway. 
 
 A RAILWAY TRAVELLING CRANE. 
 
 Here we see a steam crane of a kind largely used upon railways. It can travel upon the 
 rails just like any railway vehicle, in fact it can form part of a fast train. When not in use 
 the tall " jib " is lowered until it rests flat upon a truck which is provided for the purpose. 
 When at work, as is clearly shown, it is clipped down upon the rails and also steadied by 
 timbers upon the ballast. 
 
 A crane, an engine and a few vans with tools, form the " breakdown train." 
 
THE ROMANCE OF 
 MODERN RAILWAYS 
 
 THE STORY OF MECHANICAL LOCOMOTION, WITH 
 A DESCRIPTION OF THE CONSTRUCTION &> WORKING 
 OF THE MOST UP-TO-DATE INVENTIONS, APPLIANCES 
 AND DEVICES FOR SECURING SPEED, FACILITY AND 
 SAFETY IN OPERATION 
 
 BY 
 
 T. W. CORBIN 
 
 AUTHOR OF 
 ; ENGINEERING OF TO-DAY," "MECHANICAL INVENTIONS OF TO-DAY, 
 
 WITH MANY ILLUSTRATIONS & DIAGRAMS 
 
 PHILADELPHIA 
 J. B. LIPPINCOTT COMPANY 
 
 LONDON : SEELEY, SERVICE fif CO., LTD. 
 1922 
 
M 
 
 PREFACE 
 
 OST middle-aged men of to-day can remember 
 the time when their one boyish ambition was 
 to be an engine-driver ; but their sons found 
 a rival interest in the flying machine and desired 
 above all things to be airmen. 
 
 Flying and flying machines, however, have not and 
 cannot have so many interesting features as are to 
 be found upon engines and trains, with the result that 
 the interest has swung back to the railway, and most 
 boys of to-day are as keen about them as ever their 
 fathers were. 
 
 It is for such boys that this book is intended more 
 than anyone else, but it is hoped, nevertheless, that 
 it may make an even wider appeal. The writer knows 
 an uncle who regularly buys a certain boys' periodical. 
 He buys it, of course, to give to his nephew, but his 
 friends notice that he always reads it through him- 
 self first, and, although this book may be intended 
 for the sons and nephews, it is quite possible that 
 some fathers and uncles may find it to their liking. 
 
 The writing of it has been a labour of love, and if 
 all readers get the same pleasure in reading it which 
 the writer got in writing it, it is going to add largely 
 to the sum of human happiness. 
 
 The writer wishes to take this opportunity of thank- 
 ing several of his engineering friends ancTalso a number 
 
 ii 
 
 465255 
 
PREFACE 
 
 of railway companies and manufacturing firms who 
 have supplied him with technical information or 
 photographs. In most cases a reference to these 
 helpers appears in the text, and it is hoped that they 
 will accept that as a grateful acknowledgment of 
 their kindness. 
 
 Thanks are due for the illustrations provided by 
 the Westinghouse Brake and Saxby Signal Company, 
 of London. 
 
 12 
 
CONTENTS 
 
 CHAPTER I 
 
 PAGE 
 
 HISTORICAL AND PROPHETIC . . .17 
 
 CHAPTER II 
 RAILWAY PIONEERING 28 
 
 CHAPTER III 
 WHERE THE LOCOMOTIVES ARE MADE ... 39 
 
 CHAPTER IV 
 How A LOCOMOTIVE WORKS 60 
 
 CHAPTER V 
 COMPOUND LOCOMOTIVES 77 
 
 CHAPTER VI 
 OIL-DRIVEN LOCOMOTIVES ..... 86 
 
 CHAPTER VII 
 
 BRAKES : How THEY WORK ..... 94 
 
 CHAPTER VIII 
 THE CONSTRUCTION or A BRITISH RAILWAY . .108 
 
 CHAPTER IX 
 How RAILS ARE MADE 122 
 
 CHAPTER X 
 THE STORY OF THE BRIDGES ... .137 
 
 CHAPTER XI 
 
 How SINGLE LINES ARE WORKED . . .150 
 
 13 
 
CONTENTS 
 
 CHAPTER XII PAQB 
 
 RAILWAY SIGNALS . . , . . . .158 
 
 CHAPTER XIII 
 AUTOMATIC SIGNALLING . . . . . .175 
 
 CHAPTER XIV 
 THE SIGNALLING OF A LARGE TEBMIJTUS . . .192 
 
 CHAPTER XV 
 RAILWAYS IN FOGGY WEATHER . . . .201 
 
 CHAPTER XVI 
 TRAFFIC CONTROL 215 
 
 CHAPTER XVII 
 THE TUBE RAILWAY 230 
 
 CHAPTER XVIII 
 WONDERS OF THE UNDERGROUND . . . .241 
 
 CHAPTER XIX 
 ELECTRIC TRAINS AND HOW THEY ARE DRIVEN . . 255 
 
 CHAPTER XX 
 A RAILWAY IN THE AIR 271 
 
 CHAPTER XXI 
 FIGHTING NATURE IN CANADA 284 
 
 CHAPTER XXII 
 LONG ALPINE TUNNELS 295 
 
 INDEX 307 
 
LIST OF ILLUSTRATIONS 
 
 A TRAVELLING CRANE ..... Frontispiece 
 
 FACING PAGE 
 
 MAKING A RAILWAY CARRIAGE . . . .32 
 
 A REMARKABLE LOCOMOTIVE ON THE MIDLAND . 48 
 
 G.W.R. EXPRESS PASSENGER ENGINE ... 49 
 
 A LARGE TANK ENGINE 56 
 
 A DOUBLE LOCOMOTIVE ...... 57 
 
 A FLOATING RAILWAY 88 
 
 CAB INDICATOR 96 
 
 AUTOMATIC TRAIN STOP . . . . . .104 
 
 A STRIKING CONTRAST 112 
 
 SAWING COLD STEEL . . . . . .128 
 
 LOFTIEST BRIDGE EAST OF THE ROCKY MOUNTAINS . 144 
 THE NEWEST KIND OF SIGNAL . . . .160 
 
 A BRIDGE OF SIGNALS 168 
 
 ILLUMINATED DIAGRAM OF SIGNALS . . . .176 
 
 FOG SIGNALS 208 
 
 A BUSY SPOT 224 
 
 KEEPING THE TUNNELS CLEAN .... 232 
 
 WHERE DO You WANT TO Go ? . . . . 240 
 
 A MOVING STAIRCASE . . . . . . 248 
 
 AN ESCALATOR IN COURSE OF CONSTRUCTION . . 256 
 
 THE QUEEN'S CARRIAGE 264 
 
 A RAILWAY IN THE AIR 272 
 
 TRACK-LAYING MACHINE ...... 288 
 
 15 
 
CHAPTER I 
 HISTORICAL AND PROPHETIC 
 
 THE history of the Railway is not a very 
 long one. About a hundred years will cover 
 it, and that, by comparison with most historical 
 periods, is very short. 
 
 It is interesting to picture to oneself the changes 
 which have been brought about by the railway and 
 then to deduct, as it were, those changes from our 
 present condition, thereby bringing ourselves back 
 to that time when we were without railways. 
 
 Travelling in those days must have been very 
 wearisome, except for very short journeys. To travel 
 a hundred miles by coach, possibly on the top at 
 night and in the depth of winter, is a prospect the 
 mere suggestion of which makes us shudder. But 
 then, we have learnt what it is to go that distance 
 in a couple of hours in a comfortably upholstered 
 seat in a nicely warmed and brightly lit compart- 
 ment. The travellers by the first coach no doubt 
 looked back upon their forefathers who went by 
 still more primitive means, in much the same pitying 
 way that we now look back upon them. 
 
 There is a more striking way of showing the rapid 
 growth of the railway than mere figures. The writer's 
 B 17 
 
HISTORICAL AND PROPHETIC 
 
 grandfather was a manufacturer in a midland town 
 (now a great railway centre) about 100 miles from 
 London, and his periodical business visits to the 
 capital were made by coach. The writer's father 
 used to tell of his first trip on the railway, when the 
 carriages were of the most primitive type, little 
 better than cattle trucks of the present day ; indeed, 
 they were worse than cattle trucks in that they were 
 open to the sky. 
 
 Again, the writer remembers, when a boy, fre- 
 quently meeting the gentleman who subsequently 
 became known as Sir James Alport, the man who 
 led the way in ministering to the comfort of the 
 passengers. He was the General Manager of the 
 Midland Railway, and it was the reforms promoted 
 by him which have led to the pleasant conditions of 
 travel which we now enjoy. 
 
 He it was who introduced the practice of running 
 third class carriages on all trains and who made the 
 third class carriages comfortable. 
 
 Thus we see that three generations is sufficient 
 to cover almost the entire history of the railway, 
 and one is enough to cover the era of improvement 
 which has so much added to the pleasure of a journey 
 from the point of view of the ordinary common person 
 who goes third class. 
 
 We are apt, when thinking about what the railways 
 have done for us, to forget the carriage of goods ; 
 we think about the matter almost entirely in terms 
 of passengers. Yet probably the ease of movement 
 of goods which the railways have brought about has 
 added to our happiness and comfort far more than 
 
 18 
 
HISTORICAL AND PROPHETIC 
 
 have the facilities for passenger travel. Before the 
 railway came each district must have depended for 
 its food, clothing and other supplies to a very great 
 extent upon its immediate neighbours. 
 
 Take the cotton of which our shirts are made, for 
 an example. It is grown probably in the interior 
 of the southern part of the United States, whence 
 it travels by train to the nearest sea-port. After a 
 voyage across the ocean it reaches Liverpool, whence 
 it goes by train to one of the cotton-spinning towns 
 of Lancashire. Having been spun and woven it 
 travels again by train to the town where we happen 
 to reside. 
 
 After making all allowance for the boats on the 
 Mississippi River, the possibility of canal carriage and 
 the sea voyage, we still see that without the railway 
 our shirts would, at least, " cost us more," even if 
 we could procure them at all. 
 
 Even still more striking is the case of the grain 
 which forms our principal food. In pre-railway 
 days the people of Sussex, for example, must have 
 had to live almost entirely upon Sussex wheat, and 
 the same with every other district. Now the great 
 wheat-growing lands of the United States and 
 Canada are able to pour their produce by means of 
 the railways into the ships at the ports, and after a 
 sea-voyage it is again distributed by rail to the 
 populous centres for consumption. In other words, 
 the food upon which we depend for life must be far 
 more plentiful than it could possibly be were it 
 not for the railways. Without them, those vast 
 areas which now grow wheat for export would be 
 
 19 
 
HISTORICAL AND PROPHETIC 
 
 untilled, for they would have no market for their 
 product. 
 
 The old method of transport by horsed wagon 
 could not possibly deal with the traffic which is now 
 handled easily by rail. 
 
 In the old days, the roads must have presented a 
 very different spectacle from what they do to-day. 
 There must have been, in addition to the coaches 
 and saddle horses which have since been displaced 
 by the passenger train, long trains of heavy wagons 
 and pack-horses doing in a small way what the goods 
 trains now do. 
 
 Parcels and other small packages were sent by 
 the coaches, and for that purpose were left at the 
 various inns, whence the coaches used to start or 
 where they used to call. 
 
 This has led to a rather curious survival which we 
 may still notice to-day. When the railways came 
 on the scene they of course took over this parcel 
 traffic, and in some cases they took over the inns 
 also, with the result that in London a number of 
 modern railway depots still bear the old picturesque 
 names of the inns whose place they have taken. 
 Thus we have, or at all events had until recently, 
 railway depots called " Castle and Falcon," " Bull 
 and Mouth," " Swan with two Necks," " Blossoms." 
 
 Another survival is the use of the words " Booking 
 Office " for the place where we buy our railway 
 tickets. It arises from the fact that when a man 
 wanted to travel by coach he used to go to the inn 
 which formed the coaching " station " and arrange 
 for his seat, which was duly entered in a book. In 
 
 20 
 
HISTORICAL AND PROPHETIC 
 
 fact, he booked his seat upon a coach just as one 
 may now book a seat in a theatre. The mere selling 
 of a ticket cannot really be called " booking," but 
 we still use the old term. 
 
 In the early days there were many people who 
 opposed railways from mere prejudice, an act which 
 their successors of to-day sorely regret. There is, 
 for example, a town in Northamptonshire which 
 used to be of considerable importance. If you were 
 to visit it to-day you would notice by the size of its 
 public buildings and churches that it was evidently 
 at one time a more prosperous place than it is now, 
 and the explanation is that when a certain great 
 railway line was projected the people of this town 
 strongly objected to it. They carried their objection 
 so far that the promoters of the line were forced to 
 divert their route, and instead of going through the 
 town they went through a village four miles away. 
 Now, if you want to go to that town you alight at 
 the station in the one-time village, now a large and 
 thriving town, and wait until a little 'bus comes 
 along to carry you to the other town which languishes 
 four miles away. The railway has " made " the village 
 and in so doing has drawn a large amount of its 
 prosperity away from the older town. 
 
 Many suburbs, too, have been " made " by rail- 
 ways. There are to the south-west of London a 
 number of what used to be little isolated hamlets 
 lying along the line of the South- Western Railway. 
 This enterprising Company had the wisdom to see 
 that these were nice places for people to live in, so 
 they electrified their local trains, increased im- 
 
 21 
 
HISTORICAL AND PROPHETIC 
 
 mensely the number of trains and, in fact, started a 
 fine service to these small places. The result has 
 been that the small hamlets have quickly grown 
 into populous districts. 
 
 This sort of thing has given rise to a new way of 
 teaching geography. The modern geography text- 
 book takes as its basis the railways. Along them 
 the chief towns are to be found, for indeed, the 
 whole structure of a country, looked at as a place 
 where people live, is built up upon a framework of 
 railways. 
 
 But there is now a strange movement of traffic 
 away from the railways and back to the roads, 
 brought about by the success of the mechanical 
 road vehicle in its various forms. The first class 
 railway passenger is more and more inclined to go 
 in his own motor, the third class man is tempted by 
 the motor omnibus and the motor char-a-banc, 
 while the steam wagon and the motor lorry are 
 successfully handling much goods traffic. 
 
 In this connection it is curious to notice that the 
 road locomotive actually preceded the railway loco- 
 motive. Richard Trevithick himself, who really 
 preceded Stephenson, seems to have made a quite 
 successful steam wagon which worked upon the 
 roads in Cornwall in the very early days of the 
 nineteenth century. It was probably the condition 
 of the roads of those days which led to the 
 quick development of the railway, but retarded 
 the improvement of the road engine for many 
 years. 
 
 The mention of the name of Trevithick brings us 
 
 22 
 
HISTORICAL AND PROPHETIC 
 
 to one of the pathetic incidents of railway history. 
 This man, who was undoubtedly a great genius, 
 worked upon the idea of steam transport with a 
 very considerable amount of success. One of his 
 engines was at work at Merthyr before that of 
 Stephenson was at work in the North. He had success 
 within his grasp, and with just a little more per- 
 sistency he would have gone down in history as the 
 inventor of the successful steam locomotive, perhaps 
 the most beneficent invention of all time. 
 
 He allowed himself to be discouraged, however, 
 while the man of stronger character pushed on in 
 spite of failures, until at last he was rewarded by 
 victory over all his difficulties. 
 
 Speaking of difficulties, it is interesting to note 
 that one, at least, of the obstacles against which the 
 early pioneers fought turned out to be purely imagi- 
 nary. They got it into their heads that a smooth 
 wheel upon a smooth rail would slip rather than 
 haul a train along. They therefore expended much 
 time, thought and expense, in the early trials, on 
 devising a suitable rack with teeth, alongside the 
 running rails, so that a toothed wheel on the engine 
 might engage with it and so propel the train along. 
 They assumed that this difficulty existed ; when at 
 last they tried it they found that the rack was not 
 necessary, and that all their efforts in that direction 
 had been sheer waste. 
 
 Another curious feature about the invention of the 
 railway is the strangely odd dimension of 4 ft. 8 J ins., 
 which is the most usual " gauge " or distance between 
 the rails. One could understand it being 4 ft. 6 ins. 
 
 23 
 
HISTORICAL AND PROPHETIC 
 
 or 5 ft. or 1 metre but why 4 ft. 8J ins. ? Why, in 
 particular, that odd half-inch ? 
 
 The answer is that it is pure accident. The old 
 ways along which horses used to pull carts at the 
 colliery where George Stephenson worked were about 
 that distance apart, and so his first engines came 
 to be made to that dimension, and as soon as a few 
 had been so made it became a matter of considerable 
 difficulty to alter it. Had it been totally unsuitable 
 it would no doubt have been changed, but it was 
 just about a convenient size, and the result is that 
 in almost all parts of the world there are railways 
 with the rails that odd distance apart. 
 
 In some places where a lighter form of railway is 
 ample for the needs of the traffic the gauge has been 
 made a metre. In some very light lines it is narrower 
 still, while in yet other parts it is rather wider, but 
 the commonest gauge, by far, throughout the whole 
 world is 4 ft. 8| ins. 
 
 The younger of the two famous engineers, by name 
 Brunei, who played a large part in the early days 
 of the Great Western Railway, was a great believer 
 in a wider gauge, and he succeeded in making the 
 gauge of that line 7 ft., but it was found to be so 
 inconvenient to be different from all the other lines 
 that eventually it was altered. There are parts of 
 the Great Western line where to-day an unusually 
 wide space is noticeable between the pairs of rails, 
 which fact is due to the reduction in the gauge. 
 
 So much for the past ; now a word as to the future. 
 As has already been remarked, there is a movement 
 of traffic away from the railway and back to the 
 
 24 
 
HISTORICAL AND PROPHETIC 
 
 road. Will it continue ? May we anticipate that 
 railways will in time become out of date ? 
 
 Unquestionably, no ! The road vehicle will never 
 displace the railway, but it will help it. There is 
 and always will be a need for means to bring the 
 traffic to the railway. A railway is by its very nature 
 fixed. It may throw off short lines and sidings 
 into various places which it passes closely, but the 
 great bulk of its traffic will always need to be brought 
 to it. Here the motor vehicle will find its greatest use. 
 
 Just before the road motor came into its own 
 there was a great movement for the construction of 
 light railways, the purpose of which was to collect 
 traffic for the heavy railways. The term " light " 
 railway was used to cover a line of usually the 
 standard gauge, but in all other respects limited. 
 The speeds were limited, for instance, so that many 
 of the safeguards rightly insisted upon in the case of 
 ordinary railways might be dispensed with. They 
 were more like street railways or tramways, along 
 which goods wagons could be hauled as well as 
 occasional passenger trains. Their chief use was to 
 serve farms and other small sources of traffic. There 
 are many such lines dotted about the country, but 
 it is doubtful if many more will be constructed, for 
 the motor vehicle has since shown that it can do all 
 that was expected of the light railway and, moreover, 
 do it more cheaply and conveniently. 
 
 There is a little line in Staffordshire where the 
 gauge is narrower than the standard, but which can, 
 nevertheless, be traversed by standard railway trucks. 
 This is done by the provision of special low wagons, 
 
 25 
 
HISTORICAL AND PROPHETIC 
 
 whose wheels are of the narrower gauge on to which 
 the standard wagon can be run bodily. This principle 
 may in time be adopted to facilitate the handling 
 of the loads as they are brought into the station by 
 the motor lorries, the whole body of the lorry, with 
 its contents, being transferred to the railway truck 
 without any intermediate packing or unpacking. In 
 like manner, the incoming goods may arrive already 
 packed in receptacles which can be moved bodily 
 on to the lorry. An enormous saving in labour will 
 thus be effected. 
 
 The question of the relative cost and convenience 
 of road and rail transport will probably be found to 
 depend mainly upon distance. If a man wants to 
 send coal a hundred miles it will almost certainly 
 pay him to put it into a railway truck and send it 
 by rail. If he wants to send it two miles a motor 
 lorry will probably serve him best. Other things 
 enter into the matter, of course, but that is the main 
 thing, and the result of it will be almost inevitably 
 that long journeys will be by rail, while mechanically 
 propelled road vehicles will do the short journeys 
 and also collect and deliver the goods for the railways 
 at the beginning and end of the long journeys. The 
 two things will work hand-in-hand. 
 
 This combination will benefit all parties. The long 
 railway journeys are the ones which pay the best, 
 so that the greater the proportion of long journeys 
 the better will it be for the railways. 
 
 Another thing to be looked for in the railway 
 world will be simplification in working. The pro- 
 vision of costly safeguards against accident has gone 
 
 26 
 
HISTORICAL AND PROPHETIC 
 
 too far. It has almost, if not quite, reached the 
 point where the number of safeguards constitutes a 
 danger. Without sacrificing, then, the safety of the 
 passengers, it may be possible to save considerably 
 on the sums hitherto spent upon safeguards. 
 
 The central fact of the matter is that the railways 
 have got to serve the public more economically than 
 they have been doing. Like everyone else in the 
 world they will have to do their share of saving in 
 order to make up for the losses of the war, and the 
 way they will have to do it will be to give an equally 
 good service at a lower cost. 
 
 Should any reader of this book be of an inventive 
 turn of mind, there is no more fruitful field for 
 ingenuity than to seek out ways by which railways 
 can achieve this end. 
 
 27 
 
M 
 
 CHAPTER II 
 RAILWAY PIONEERING 
 
 OST of the matter in this book relates to 
 railways in the highly developed, thickly 
 populated parts of the world where every 
 inch of the country was well known before the line 
 was laid, and where the possibility of " the un- 
 expected " was confined to the chance of striking 
 an underground spring in a tunnel. 
 
 Very different is the work of constructing and 
 maintaining a line away in the wilds where the 
 railway surveyors are often the first civilized men to 
 set foot along the line which the railway will shortly 
 follow. 
 
 To illustrate this kind of work we may well take 
 one of the most valuable and at the same time most 
 wonderful of these pioneer lines, the Grand Trunk 
 Pacific, of Canada. 
 
 As everyone knows, Canada has been the young 
 giant of the past few decades. No country in the 
 world has ever grown so quickly, for perhaps no other 
 country has such a valuable combination of mineral 
 resources, fertility, extent and climate. Moreover, it 
 is so situated that it makes a powerful call upon 
 men and women to come and occupy its empty 
 spaces and to develop its wealth. On the one hand 
 
 28 
 
RAILWAY PIONEERING 
 
 is the United States, actually adjoining, with a vast 
 population and its own empty spaces nearing complete 
 occupation. What wonder that some of its more 
 restless and adventurous spirits should drift over the 
 border to the new country ! Then it is so handy 
 for " home," as the colonist insists on calling Great 
 Britain. A man who emigrates to Australia feels 
 himself cut off, probably for the rest of his life, from 
 his kith and kin, but to run home from Canada is 
 little more than a week's journey. Small wonder, 
 then, that British people by the thousand have flocked 
 out to this new land of promise. 
 
 The older, eastern parts of Canada have, of course, 
 had their railway systems for years, and that wonder- 
 ful line, the Canadian Pacific, stretched like a steel 
 band right across the continent ; but there still 
 remained, in the year 1900, room for another great 
 main line across from east to west, following a some- 
 what different route and tapping fresh areas. 
 
 The Grand Trunk Railway was already in existence, 
 indeed it was the first railway in the colony, but its 
 system served almost exclusively the older part on 
 the east. The idea of its extension westward came 
 to the mind of Mr. C. M. Hayes, an American railway- 
 man who had been brought in to rescue the Grand 
 Trunk from a poor financial position into which it 
 had fallen. 
 
 This far-seeing administrator perceived the opening 
 for a new line across Canada ; he perceived, too, 
 what a splendid addition it would be to the country's 
 wealth-earning machinery, and so, with characteristic 
 energy, he set out to push his idea. 
 
 29 
 
RAILWAY PIONEERING 
 
 It was so good y however, that he found no great 
 difficulty in carrying his scheme through ; the 
 Government of the colony and financiers in London 
 being alike ready to help. Thus it came about that 
 early in the present century the great undertaking 
 was commenced which would provide a complete 
 new route, All- Canadian, from Halifax in Nova 
 Scotia on the Atlantic to a new port at Prince Rupert 
 on the Pacific. Part of the work was undertaken 
 by the Canadian Government and part by the Grand 
 Trunk Pacific Railway Company, the arrangement 
 being that the part constructed by the Government 
 should, when finished, be leased to the Company 
 for a term of fifty years on certain terms, so that the 
 whole line should be operated by the Company as 
 a single system. 
 
 Now a good deal of the country through which 
 this line had to pass was practically unknown. 
 There were maps, it is true, which had been made by 
 survey parties at various times for the Government, 
 but these were found to be so faulty and incomplete 
 that the railway surveyors quickly abandoned them 
 altogether and made a completely new survey, 
 itself a heavy and laborious task. 
 
 The first step was to make a preliminary recon- 
 naissance. The general direction of the route had 
 been decided upon and parties were sent over this 
 route to have a preliminary look at it, so to speak. 
 They were quite small, consisting usually of a 
 surveyor and one assistant, with perhaps a few men 
 to help to carry things. They travelled as " light " 
 as possible, their only apparatus being an aneroid, 
 
 30 
 
RAILWAY PIONEERING 
 
 with which to measure roughly the ups and downs 
 of the route, and a compass. Distances were roughly 
 estimated or paced out. 
 
 Not only had they to follow the route suggested, 
 but they were instructed to range over the country 
 fifty to one hundred miles on either side in case any 
 better route should be available. 
 
 The country through which they passed was 
 largely uninhabited, except by a few Indians and 
 trappers. Many miles of it was virgin forest pene- 
 trated sometimes by tiny footpaths, but more often 
 by no track of any sort. On the contrary, the fallen 
 trees formed in many places obstacles which they 
 could only pass at the rate of a few yards per hour. 
 The storm and the fire fiend had played tricks with 
 the forest giants at some time or other and had 
 piled them together in confused masses. 
 
 In other parts, too, they encountered swamps, 
 through which progress was only just short of im- 
 possible swamps, as one writer has put it, " big 
 enough to submerge an English county in." 
 
 These features would be varied by rough rocks 
 with surfaces slippery with decaying vegetation, 
 while rivers broad and swift would confront the 
 traveller with startling suddenness. These they would 
 have to get across as best they could, the most 
 usual form of progress being by means of a raft 
 roughly fashioned as needed from logs gathered in 
 the vicinity. 
 
 Travel was on the whole easier in winter than in 
 summer. In summer the ground was apt to be wet 
 and soft, but on the other hand, although winter 
 
 31 
 
RAILWAY PIONEERING 
 
 with its frost made the ground firm and hard it also 
 brought the blizzard and the snowstorm, the snow- 
 drift and the frost-bite. Temperatures ranging 
 down to 35 degrees below zero bring dangers of their 
 own. 
 
 Speaking generally, the area traversed was from 
 300 to 400 miles beyond the edge of civilization, so 
 that each little party was completely isolated, and 
 should an accident have happened the news might 
 have taken months to reach their fellow-men, if, 
 indeed, it ever reached them at all. 
 
 After this preliminary reconnaissance had been 
 completed a more definite line of route was pro- 
 visionally decided upon, and then parties set out 
 upon the " first location " with a view to a more 
 definite decision still. 
 
 These parties consisted of about twenty men in 
 each, and they took with them complete surveying 
 apparatus, theodolites, levels and the like, by means 
 of which they made accurate plans of what they 
 considered would be the best course for the railway 
 to follow. If there were several possible alternatives 
 they surveyed them all, sending the plans, together 
 with a report, to the engineer-in-chief for con- 
 sideration. 
 
 These reports had to give the fullest possible 
 details of the country, particularly the levels and 
 gradients, the geological formation, notes as to the 
 facilities for the construction of bridges, in fact all 
 manner of information which might have the slightest 
 bearing upon the construction of the line. In 
 addition to this the reports were required to include 
 
 32 
 
RAILWAY PIONEERING 
 
 references to the character of the country and its 
 possibilities from a commercial point of view, for, 
 of course, the promoters wanted to run their line 
 so as to tap the most profitable traffic. 
 
 For transport they were provided with sleighs 
 and toboggans and any other form of transport 
 suitable to the area in which they were working. 
 
 After one party had been over the ground and 
 had reported upon a location another party did the 
 same thing in order to check the first. Sometimes 
 even a third went over it so as to arrive at a third 
 opinion. 
 
 Even then, however, the matter was not finally 
 settled, because a survey party went ahead of the 
 construction people in case, even at the last moment, 
 an improvement of some sort should be found possible. 
 
 When fixed upon by the surveying parties the line 
 for the railway was indicated by a row of stakes 100 ft. 
 apart, and where possible a rough preliminary clearing 
 was made to form a track 100 ft. wide, while every 
 1000 ft. a peg was put in with the altitude marked 
 on it. 
 
 The support and provisioning of the survey 
 parties was in itself a most formidable task, yet it 
 was one upon which the ultimate success of the 
 railway largely depended. Just think for a moment. 
 A thousand odd men, split up into small parties, 
 spread over a line about 2000 miles long, most of 
 them working in virgin country, amid forests and 
 swamps, in rocky defiles and on rushing rivers. Yet 
 being men they had to be fed and kept in health 
 and good spirits. 
 
 c 33 
 
RAILWAY PIONEERING 
 
 Much use was made of Indians. As a matter of 
 fact, a considerable part of this line runs through 
 the territory reserved for the Indians. When the 
 Canadian Pacific line was made, many of these 
 people were induced to leave the line of that railway 
 and settle in these more remote parts, the idea being 
 that they would never need to be disturbed there. 
 With the development of the country outrunning 
 the wildest anticipations, however, the time came 
 when it was desirable to run the line through the 
 new Indian reserve, and it needed much diplomacy 
 to get their sanction. This was ultimately obtained, 
 and in the preliminary surveys particularly the 
 Indians, with their intimate local knowledge, their 
 hardy well-trained frames and their indifference to 
 hardship, rendered very valuable service. 
 
 Another class of men who were found to be of the 
 greatest value were the trappers and other men in 
 the employ of the Hudson Bay Company. Many of 
 these men had spent years in the wilds, had re- 
 markable local knowledge and an admirable system 
 of intercommunication between the isolated posts, 
 the growth of many years of experience. 
 
 Still, the railway engineers, while making every 
 use of the Indians and trappers, had to depend 
 mainly upon their own efforts. So they made roads 
 of a sort, through the forest, from convenient points, 
 cutting the line of the survey at intervals. True, 
 these roads were only a few feet wide, just enough 
 to get a sledge along, but they served as the lines 
 of supply. At the ends of them were formed depots 
 or " caches " where food and other necessities were 
 
 34 
 
RAILWAY PIONEERING 
 
 stored, and from these depots the parties drew their 
 supplies as they needed them. 
 
 The roads were supplemented by small flat-bot- 
 tomed steamers, which were able thus to use some of 
 the rivers, while other parts again were best reached 
 by canoes. 
 
 It must not be thought, however, that these were 
 pleasure trips on the rivers. On the contrary, the 
 canoe men often had the roughest experience* 
 particularly when " portage " was necessary. This 
 operation consists in unloading the canoe, carrying 
 the cargo over or around some obstacle, then doing 
 the same with the canoe itself, which is finally 
 re-launched and re-loaded. Sometimes this may be 
 done to pass some rapids, or it may be necessary to 
 leave one stream and change on to another, and the 
 men may have to carry the stuff anything from a 
 few yards to a mile. Given a heavy canoe, with a 
 ton of stuff on board and a crew of two men, it is 
 easy to realize that the work is arduous. 
 
 In winter, with the ground hardened by frost, 
 dog sleighs were largely used. 
 
 At certain strategic points doctors were stationed. 
 The clean fresh air and hard life on the whole made 
 cases of illness few and far between, but, of course, 
 there were some cases and accidental injuries were 
 unavoidable. 
 
 In spite of all this care and forethought, however, 
 things went wrong occasionally. In one case, at 
 least, a surveying party were nearly lost through 
 starvation. They strayed too far away from their 
 depot, probably led on by the interest of the work 
 
 35 
 
RAILWAY PIONEERING 
 
 and misled by a wrong calculation as to the amount 
 of food which they had with them. Realizing, at 
 last, their danger, they retraced their steps through 
 a snowstorm, but several days' march brought them 
 no succour until, fagged out and longing for sleep, 
 they heard voices in the forest. It is to be regretted 
 that the voices were swearing, as it turned out, at the 
 dogs which were drawing a sledge-full of supplies. 
 Thus help came in the nick of time and the whole 
 party were saved, but it was a narrow escape. 
 
 Another danger which was always present during 
 this work was the bush fires which are so prevalent 
 in those regions. If once a fire gets going when the 
 wood is dry, it spreads with astounding rapidity 
 and may overtake or encircle an unfortunate party. 
 Little can be done, unless large forces of men are at 
 hand, to stop the spread of the fires. The only thing 
 to do is to keep a sharp look out, and on perceiving 
 danger to flee. 
 
 In this connection it may be interesting to remark 
 that the Canadian Government are hoping to evolve 
 a method of fighting these fires from the air. Aero- 
 planes patrolling the forests can detect the fires at 
 great distances, and it is hoped that by dropping 
 suitable chemical bombs they may be able to ex- 
 tinguish them, 
 
 It was during the operations of these survey parties 
 that many valuable discoveries were made. Minerals 
 of one sort and another were found, here and there, 
 but the greatest discovery of all was that underlying 
 a large extent of forest was what came to be called 
 the " clay belt." This meant that many thousands 
 
 36 
 
RAILWAY PIONEERING 
 
 of square miles of land which had been thought to 
 be only fit for growing wild timber was found to be 
 capable of cultivation. Indeed, its nature was such 
 that it is not only capable of growing valuable crops, 
 but is particularly fertile. 
 
 This discovery meant an enormous addition not 
 only to the future traffic of the railway, but to the 
 wealth of the country. 
 
 What has been said so far relates mainly to the 
 part of the line which traverses the fairly level 
 country. In order to reach the Pacific Coast it was 
 necessary, somehow, to penetrate the vast rocky 
 barrier known as the Rocky Mountains. 
 
 The promoters had made up their minds that by 
 hook or by crook they would find a way through 
 rather than over this mighty range. The Canadian 
 Pacific line and also the United States lines which 
 run from east to west had had to climb, more or less, 
 over the range. Of course, they took advantage of 
 the passes, the lower parts between the peaks ; but 
 do what they could, they had a stiff climb on both 
 sides of the range. 
 
 Now even a slight incline is an abomination on a 
 railway. It involves huge expense. Engines have 
 to be specially big and heavy just because of a few 
 miles of steep gradient, extra engines have to be 
 employed and the cost for fuel is enormous. On 
 this line it was decided that a way should be found 
 not steeper than 21 ft. rise per mile. That seems a 
 very easy gradient, in all conscience, with which 
 to scale the snow-capped Rocky Mountains, and 
 one wonders at the optimism of the men who set 
 
 37 
 
RAILWAY PIONEERING 
 
 themselves the apparently impossible task of finding 
 such a route. But they did it. 
 
 Over 10,000 square miles of country was closely 
 examined to find the best route. Forty passes 
 were investigated and surveyed. Then the forty 
 were reduced to six ; then to three, until the final 
 choice fell upon the Yellowhead Pass, through which 
 the line passes without exceeding the very low 
 limit of gradient which has been mentioned. 
 
 After this description of the preliminary work, we 
 may well devote a further chapter to the work of 
 construction to which it led up. (See chap, xxi.) 
 
CHAPTER III 
 WHERE THE LOCOMOTIVES ARE MADE 
 
 IN this chapter we will take a stroll through 
 the locomotive works of one of the leading 
 British railways. It is an account of an actual 
 tour of inspection made for the express purpose of 
 leading our readers in thought through the same 
 interesting experience. 
 
 We enter a large door leading into the " Machine 
 Shop," the large building in which are the bulk of 
 the " machine tools " by which the various parts 
 of the engines are fashioned before they pass to the 
 Erecting Shop to be put together. It is a large 
 single story building, a good deal of glass making 
 it light and cheerful. The roof is supported on rows 
 of columns, the upper parts of which also serve to 
 carry the overhead shafting and pulleys by which 
 the power is transmitted from the electric motors 
 dotted about the shop to the machines. 
 
 The spaces between the rows of columns form 
 aisles and the machines are set out in long rows, 
 generally speaking, two rows in each aisle with a 
 passage way between the two. Thus the floor is 
 well covered with machinery, while above, just 
 beneath the roof, is a maze of moving belts. 
 
 The first machines encountered are what are 
 
 39 
 
WHERE THE LOCOMOTIVES ARE MADE 
 
 termed " automatics," for they go on making certain 
 articles over and over again without any attention, 
 or to be more precise with only occasional attention. 
 
 The articles made by them are such things as 
 bolts and pins, of which every engine contains a 
 large number all alike. It is no use employing an 
 automatic lathe for anything unless you want 
 thousands just the same, for the original " setting 
 up " of the machine takes a lot of time and is not 
 worth doing for only a few. 
 
 Let us take a closer view of these mechanical 
 wonders. As most people know, a lathe is a machine 
 in which a piece of metal is turned round in order 
 that a steel tool may be moved in contact with it in 
 such a manner as to take a cut off it. In ordinary 
 lathes the tool is held in a sort of carriage capable 
 of moving in all directions at the will of the operator, 
 and the work is then largely done " free-hand," the 
 tool being altogether and entirely under the personal 
 guidance of the workman. Such machines are em- 
 ployed in all engineering works and are absolutely 
 essential for all general work. They are the most 
 numerous form of machine tool in all engineering 
 works and are to be seen in all sorts and shapes, 
 adapted for different classes of work. Some are 
 made specially for turning long but comparatively 
 thin articles, others are for turning short things of 
 large diameter, some are for small things, some for 
 large, some have a screw which propels the carriage 
 along in such a manner that it can cut accurate 
 screw threads, others lack this device, and so on. 
 
 They are all alike, however, in that they possess. 
 
 40 
 
WHERE THE LOCOMOTIVES ARE MADE 
 
 a " bed " and a " headstock." The former may be 
 described as a long, low bench, made of iron, the 
 upper surface and the edges of which are planed 
 quite flat and straight. 
 
 The headstock sits upon the bed at the left-hand 
 end. It consists of a spindle, carried in bearings, 
 so that it can turn round freely and truly, pulleys 
 for driving it round and a screwed end on to which 
 can be placed some device for holding the article to 
 be turned. The spindle is, of course, horizontal and 
 parallel with the centre-line of the bed. Special 
 appliances are often made, to screw on to the end of 
 the spindle, to facilitate the holding of certain 
 objects, but for general purposes there are always 
 two. The first of these is called a " face-plate " and 
 consists of a disc of iron, as large as the machine will 
 accommodate, with a lot of holes and slots in it 
 through which bolts can be passed for the purpose 
 of fixing the work upon it. 
 
 The other thing is called a " chuck," why, the 
 present writer has no notion. It certainly does not 
 " chuck " things about, for its duty is to do the exact 
 opposite, to hold them firmly. A round drum-shaped 
 object, it has three or four jaws which, by the opera- 
 tion of a key, can be made to advance or recede 
 along radial lines to and from the centre. When a 
 workman is instructed, therefore, to " chuck " a 
 certain thing he does not throw it or leave it alone, 
 but having drawn the jaws back sufficiently far, he 
 inserts the object between them and then moves 
 them towards it until they grip it securely. In 
 some cases all the jaws move together, so that 
 
 41 
 
WHERE THE LOCOMOTIVES ARE MADE 
 
 anything round, if gripped by them, must be central 
 with the spindle. 
 
 For turning long objects a further support is 
 required, and that is furnished by the " tailstock," 
 a strong support of iron carrying a steel point or 
 " centre." The whole thing can be moved at will 
 along the bed and fixed at any point, and the " centre " 
 itself can also be moved a few inches by means of a 
 screw and a hand-wheel. 
 
 Thus, a long object is fixed by some suitable means 
 in the headstock, while the tailstock is brought up 
 until the back " centre " just fits nicely in a little 
 dimple made for the purpose in the right-hand end 
 of the object. Thus, while supported at its outer 
 end the object is still free to move. 
 
 When a number of small articles are required all 
 alike a semi-automatic lathe comes in useful. Of 
 these there are a number to be seen as we pass along 
 on our journey. They have headstocks and beds, 
 very much like the general-purpose lathes which 
 have just been described, but in addition they have a 
 strange-looking cylindrical object mounted upon the 
 carriage instead of the simple arrangement for 
 holding the tools which we have just been looking at. 
 
 This curious object is called a " capstan," or 
 sometimes a " turret," and if you look carefully at 
 it you will notice there are five or six holes in it set 
 all round it at regular intervals. 
 
 Each of those holes is intended to hold a tool, so 
 that the tools for five or six operations can be held 
 at the same time. Moreover, the capstan turns 
 round on the movement of a certain handle in such 
 
 42 
 
WHERE THE LOCOMOTIVES ARE MADE 
 
 a manner as to bring each tool into operation in 
 succession. 
 
 Just look at the saving of time which that means ! 
 In the ordinary lathe the man carries out one opera- 
 tion, then, in all probability, he has to take out the 
 tool, get another one and fix it in its place. Quite 
 a small object may call for four or five operations, 
 each needing a different tool or the tool in a different 
 position, and in an ordinary lathe the workman 
 would spend the greater part of his time, were he 
 making a number of small things, in changing his 
 tools. 
 
 If he has a capstan lathe, however, each tool 
 comes into position as needed at the mere motion of 
 a handle. Not only so, in the great majority of such 
 machines the material from which the article is to 
 be made, generally a rod or round bar, is automatically 
 moved into position and then gripped, again by 
 simply two motions of a handle. 
 
 Let us go a little further on and watch a man 
 making some small bolts in a machine of this kind. 
 The material is a bar of steel, not round, but hexagon, 
 the shape of the heads on the bolts. He has just 
 finished one, so he pulls a lever and the bar, which 
 passes through a hole right down the centre of the 
 spindle, moves forward until just enough projects 
 from the chuck to enable the next bolt to be made. 
 Another movement of the handle and the bar is 
 gripped correctly. A movement of another handle 
 and the capstan advances, bringing with it a tool 
 which takes a deep cut off the metal, bringing it to 
 somewhere near the right size. The next movement 
 
 43 
 
WHERE THE LOCOMOTIVES ARE MADE 
 
 of the handle causes the capstan to retire, and as 
 it does so it turns round just enough to bring the 
 next tool into operation, after which it comes up to 
 its work once more and takes another cut, this time 
 making it just the right size. Another motion and 
 a third tool comes into play, this time to make the 
 thread. And so it goes on until the thing is finished, 
 when a tool comes across, cuts off the finished bolt 
 and leaves the end of the bar ready to be brought 
 forward for another one. 
 
 In the semi-automatic lathe these things are all 
 done by a man working a handle or handles to and 
 fro. The man does the same succession of things 
 over and over again like a machine, so that it is 
 quite a natural step to make the machine itself 
 pull the handles, and when we do that we arrive at 
 the fully automatic lathe such as we see in these 
 works. 
 
 In place of the man there is a series of drums 
 underneath the machine with slanting strips fixed 
 upon them, so that as they turn they occasionally 
 encounter the end of a lever and push it to one side. 
 The fixing of these strips, or " cams " as they are 
 called, is a matter requiring both patience and skill 
 if they are to do their duties correctly, because, as 
 is quite obvious, the success of the whole thing 
 depends upon each one coming into operation at 
 precisely the right moment. 
 
 Thus, as we watch the machine at work we notice 
 one of these cams coming slowly round ; presently 
 it touches the end of a rod, slowly the rod is pushed 
 over and a new operation commences ; a moment 
 
 44 
 
WHERE THE LOCOMOTIVES ARE MADE 
 
 later another cam moves another rod and a further 
 operation takes place. And so the machine goes on 
 until the bar which forms its material has been all 
 used up. One skilled man can set up a number of 
 these machines and it is sufficient if quite an un- 
 skilled person just keeps an eye upon a number of them. 
 
 But we must get on beyond the lathes, of which 
 we pass a large number of all sorts. The next thing 
 we see is a planing machine. You know those long, 
 flat rods, " side-rods " they are called, which connect 
 the wheels of a locomotive together. When two 
 boys want, in play, to imitate an engine, they often 
 stand one behind the other, each hand grasping the 
 end of a stick, one stick on each side of them. Then 
 as they run along making a puffing noise they make 
 their hands go round like the cranks on the sides of 
 the engine. The sticks in that case represent the 
 side-rods. 
 
 The operation which we are now looking at is 
 planing some rough bars of iron or steel to make 
 them flat and straight so that they will do to form 
 side -rods. Planing metal is not quite like planing 
 wood, a much better known operation, because even 
 the most powerful machine can only take off a narrow 
 strip at a time, instead of the broad shaving which 
 we take off wood. Otherwise, however, the work 
 is just the same. In the planing machine there is a 
 strong, heavy table of iron, flat upon its upper 
 surface except for a number of slots, shaped like a 
 letter T upside down, into which bolts can be slipped 
 for the purpose of holding down the work being 
 planed. 
 
 45 
 
WHERE THE LOCOMOTIVES ARE MADE 
 
 The table is so arranged that it can slide to and 
 fro upon long guides formed in the base of the 
 machine. Under the table are wheels and gear by 
 which the table can be propelled, while at the side 
 is a trigger-like arrangement by which the direction 
 can be changed. Look at it now, as the table is 
 coming towards us. Suddenly a projection upon the 
 side of the table works the " trigger " and the table 
 stops, but only for a moment, for it quickly starts 
 to return whence it came. But watch it still. 
 Presently another projection trips the trigger once 
 more and once again the table comes forward. 
 Thus as long as the machine is working, without any 
 attention from the attendant, the table keeps moving 
 to and fro. Moreover, by adjusting the position of 
 the projections upon the side of the table the workman 
 can make the length of the stroke what he will. 
 
 Now let us turn our attention to the bridge, as we 
 might call it, which spans the table. 
 
 Springing up from the base of the machine, one 
 on either side of the table, are two strong pillars, 
 while between them there stretches a strong iron 
 beam, generally spoken of as the " cross-rail." It 
 is these which form the " bridge-like " object, and 
 their purpose is to carry the tool, which takes a 
 cut off the object as it slides beneath. The carpenter 
 moves his plane over the wood, in this machine the 
 work moves beneath a stationary tool. 
 
 The tool is actually fixed in what is termed the 
 " tool-box," which is carried upon the cross-rail. 
 It can slide along the cross-rail, propelled by a screw, 
 and at every backward journey of the table another 
 
 46 
 
WHERE THE LOCOMOTIVES ARE MADE 
 
 trigger-like arrangement is set in motion, giving the 
 screw a slight turn, so moving the tool-box and tool 
 a little way along the cross -rail. Thus the tool 
 makes cut after cut, each one straight and parallel 
 to the last one, and so the whole surface is covered 
 with parallel cuts until it is quite smooth. If it 
 only needs to be generally flat the cuts are fairly 
 coarse, but if a very smooth finish is required they 
 are fine and close. 
 
 The cross-rail itself can be raised and lowered by 
 means of screws operated by a hand-wheel, and 
 there is another screw still in the tool-box, by which 
 slight vertical adjustments can be made. 
 
 Thus we see how the side-rods are made flat, 
 straight and smooth. To save time on the part of 
 the workman a number of them are set upon the 
 table side by side and the machine planes right 
 across the lot. 
 
 Then, as you will remember, there is a hole in 
 each end of the rod, where the pin goes which projects 
 from the side of the wheel of the engine. It is very 
 necessary that those two holes should be precisely 
 the correct distance apart. The next machine that 
 we come to ensures this. It is a special form of 
 drilling machine for this work. The rod is fixed in 
 place by being bolted against a flat surface provided 
 for the purpose, and then two spindles commence 
 to rotate. Each of these spindles carries a tool which 
 slowly advances until it has passed right through the 
 bar and has cut out a nice round, smooth hole. 
 Both spindles work at the same time, and having 
 once been fixed at the correct distance apart any 
 
 47 
 
WHERE THE LOCOMOTIVES ARE MADE 
 
 number of rods can be drilled without any risk of 
 the holes being other than the right distance apart 
 too. Of course, it would be possible to drill each 
 end separately, but then the workman would have 
 to be exceedingly careful in measuring the positions 
 for the holes, and if he were to make a mistake the 
 whole rod with all the work already put upon it 
 would be wasted. 
 
 Thus the special machine with two spindles saves 
 a lot of time, a very important point in all manu- 
 facturing work. And speaking of saving time, I 
 wonder if you noticed just now when looking at the 
 planing machine that as it came forward, taking a 
 shaving off the bars, it moved fairly slowly, but as 
 soon as it reversed it seemed to hurry up, doing the 
 return stroke, when no work was being done, in less 
 than half the time. That again is an instance of the 
 saving of time and therefore cost. 
 
 But what is this curious thing ? It looks like a 
 box of a rather strange shape of a roughish grey 
 metal. Through it are two large holes. It is a 
 casting for one of the cylinders of an engine. We 
 shall see castings being made presently, in the 
 foundry, but here it is being bored, for those two 
 large holes are perhaps the most important things 
 in the whole engine. One is the cylinder where the 
 steam pushes against the piston, and by doing so 
 moves the train, while the other is where the valve 
 works which sends the steam first into one end arid 
 then into the other, at the same time liberating the 
 steam which has done its work. 
 
 Those holes have to be bored out very truly and 
 
 48 
 

WHERE THE LOCOMOTIVES ARE MADE 
 
 very accurately, and here again, the two must be a 
 precise distance apart. The casting is, therefore, 
 fixed in a special machine with two spindles, one of 
 which bores out each hole. 
 
 And now we may notice that we are getting to a 
 part of the shop where heavier work is done, for the 
 roof is higher and high up overhead there is an 
 electric travelling crane, the duty of which is to lift 
 about the shop any heavy parts which may need to 
 be handled. Two run-ways, composed of strong 
 girders, run along each side of this higher portion, 
 while spanning from one to the other is a pair of 
 steel girders forming, as it were, a bridge across the 
 shop, the ends of the bridge being supported upon 
 carriages which run on rails upon the top of the run- 
 ways, so that the whole thing can run up and down 
 the whole length of the building. Further, upon the 
 bridge, is a trolley, the wheels of which run upon 
 rails upon the bridge, and upon it are the motors 
 and lifting gear, also the cabin for the driver. 
 
 Since, then, the bridge can run from end to end 
 of the shop and the trolley can run from side to side 
 upon the bridge, it follows that the trolley can place 
 itself over every part of the shop (that is, of course, 
 the higher portion) and lift anything from any part, 
 carry it along and deposit it upon any other part. 
 The whole thing is worked by electricity and can 
 be perfectly controlled by the man in the cabin. 
 
 We must not spend too much time in this shop, 
 
 but there are several things we ought to note as we 
 
 pass on. One is a curious form of lathe, called a 
 
 vertical boring mill. It is just like a lathe, except 
 
 D 49 
 
WHERE THE LOCOMOTIVES ARE MADE 
 
 that its spindle is vertical, so that its face-plate 
 forms a round table. Its special virtue is that it is 
 so much easier to fix an object down upon a horizontal 
 surface than upon a vertical one. You would find 
 it easier, for instance, to fix an object weighing half 
 a hundredweight upon a table than you would upon 
 a wall. Being easier it can be done more quickly, 
 and so time is saved. 
 
 Another machine is called a slotting machine. 
 Its purpose is to plane small articles, but it differs 
 from a planing machine in that the work is fixed 
 while the tool goes up and down. It is more often 
 called upon to plane grooves and slots in an article 
 than to plane a smooth, flat surface, whence we see 
 why one machine is called a planer, but the other a 
 slotter. 
 
 These are not, of course, all the tools in the shop 
 by any means, but only just the more prominent 
 ones. 
 
 As we step out of the door on our way to the next 
 place of interest we are startled by a succession of 
 deep thuds accompanied by a distinctly felt vibration 
 of the floor, which, by the way, is here the solid 
 earth. That is no cause for alarm, however, for it 
 simply betokens our approach to the large forge 
 where the steam hammers are at work. 
 
 Have you ever watched I expect you have a 
 workman in the street standing with his legs well 
 apart pounding away at the paving between his feet 
 with a heavy rammer ? A steam hammer is simply 
 that man made strong. 
 
 It consists of a powerful iron cylinder supported 
 
 50 
 
WHERE THE LOCOMOTIVES ARE MADE 
 
 upon two strong legs set well apart. . Inside the 
 cylinder is a piston just like that of any other steam 
 engine. The cylinder is so placed that the piston 
 goes up and down, and the piston rod is very stout 
 and strong. To the lower end of the piston rod is 
 attached the " head " of the hammer, which may 
 weigh several tons. 
 
 The inlet of steam into the cylinder is controlled 
 by a handle which, as we look, is in the grip of the 
 hammer-man. A slight movement of his hand and 
 up goes the heavy hammer-head, for he has let the 
 steam in under the piston. There for a moment he 
 holds it while his mates adjust the lump of hot iron 
 upon the anvil which stands between the " feet " of 
 the machine. When all is ready there is just a 
 flick of the wrist and down comes the hammer, 
 and the great lump of iron squashes as if it were 
 putty. 
 
 It is most fascinating to watch, for in the hands 
 of a skilled operator the hammer is almost human. 
 He seems to be able to " play upon it " like an 
 instrument and to make it do anything, from gentle 
 taps, almost tender in their softness, to hard, vicious 
 thumps into which the machine seems to put all 
 its force. 
 
 It is a draw-hook which they happen to be making ; 
 one of those strong hooks by which an engine is 
 coupled to its train. The heavy bar of iron, soft 
 from the heat of the furnace whence it has just been 
 drawn, changes its shape as we watch almost as if 
 the workmen were wizards rather than ordinary 
 human beings, and it is all due to the wonderful 
 
 Si 
 
WHERE THE LOCOMOTIVES ARE MADE 
 
 power and docility of these great machines. There 
 are several other ones at work, too, but we have 
 not time to stay. 
 
 In the next shop we visit they are making what 
 are termed " drop-forgings," small parts made of 
 wrought iron, the shape of which is against their 
 being turned out of a bar. The hammers used for 
 this are quite different from the steam hammers 
 which we have just left. The " head " slides up and 
 down between guides, and the mechanism is so 
 arranged that it is lifted up several feet and then 
 allowed to drop of its own weight. Hence they are 
 called " drop-hammers " and the forgings made by 
 their aid are " drop-forgings." 
 
 A sort of sandwich is made consisting of a piece of 
 white-hot iron and two pieces of steel. The pieces 
 of steel are in reality dies with depressions cut in 
 them of a certain shape, so that when the whole 
 " sandwich " is compressed under the blows of the 
 hammer and the soft metal is pressed into the 
 depressions the desired shape is formed. 
 
 Next we see " flanging presses," in which thick 
 steel plates, after being made hot, are pressed into 
 curious shapes almost as easily as one can shape 
 tinfoil between the fingers. 
 
 These are parts for the boiler shop, into which we 
 pass next. As usual with boiler shops, the chief 
 feature which strikes the visitor is the noise. The 
 hammer is a famous tool in the hands of a boiler- 
 maker. It may be that he is flattening a plate, or 
 trimming its edge, or caulking the joints, or closing 
 down a rivet, or putting in stays, whatever it is he 
 
 52 
 
WHERE THE LOCOMOTIVES ARE MADE 
 
 may be doing it is almost sure to be a hammer that 
 he is using. 
 
 Then the hand hammer is powerfully reinforced 
 by the pneumatic " pistol " hammer, so called 
 because the workman holds it in his hand like a 
 pistol. Like a pistol, too, it has a trigger, upon 
 pressing which a little steel hammer-head inside the 
 tool strikes rapidly upon the chisel or riveting tool 
 or whatever it may be that is placed in the " muzzle." 
 The result is a fierce growl, more menacing than 
 the cry of the noisiest animal, yet it is simply doing 
 some useful and beneficial work. 
 
 Look at that man, for example. He is putting in 
 some rivets to fasten together two steel plates which 
 will shortly form part of a boiler. There are holes 
 along the edge of both plates, carefully drilled so 
 that they will coincide. Into these holes are placed, 
 one at a time, of course, hot rivets. The man with 
 the pistol then holds its muzzle (or rather a tool 
 stuck in the muzzle) against the end of the rivet, 
 presses the trigger and amid a terrific din the solid 
 steel just flattens down into a pan-shaped head. 
 
 But we must hurry on, simply pausing to notice 
 the shearing machine. Here a pair of steel jaws 
 are continually opening and shutting. A man 
 places a piece of steel plate three-quarters of an inch 
 thick between them, and in less time than it takes 
 me to write this the plate is bitten cleanly in two. 
 
 The iron foundry takes our attention next. It 
 is a lofty building with an electric crane overhead, 
 but it must be confessed that it is dirty. It is " clean " 
 dirt, however, for it is due to the dust of the black 
 
 53 
 
WHERE THE LOCOMOTIVES ARE MADE 
 
 sand of which the floor is composed and of which 
 the moulds are made, and that is kept sweet and 
 healthy by frequent contact with molten iron. 
 
 All over the floor are men or little groups of men 
 making the moulds. Let us watch one. He is only 
 doing a simple job, but it will serve to illustrate all. 
 He is making some brake blocks for a tender, those 
 things which press against the wheels when it is 
 desired to check the speed. 
 
 Lying upon the floor is a board with some curiously 
 shaped projections upon it, which upon closer 
 examination prove to be each one -half of a brake 
 block. Those projections are the " patterns " which 
 in this case are for convenience mounted upon a 
 board. 
 
 Then he takes an iron box which he carefully 
 lays down upon the board, with its open end down- 
 wards. The other end of the box, the bottom we 
 might call it, now lies upwards, and we notice that 
 it has no bottom in the usual sense, but instead a 
 number of crossbars with spaces in between. He is 
 now filling the box with sand, passing it in between 
 the crossbars, spreading it so that it covers the 
 patterns entirely. Now he takes up a rammer and 
 with it beats the sand as hard as he can, adding more 
 and more sand until the box is quite full of sand 
 now as firm, almost, as a brick. 
 
 Next he carefully lifts the box off the patterns 
 and turns it over, revealing a surface of sand with 
 depressions in it, each of them being a negative, so 
 to speak, of half a brake block. This is the bottom 
 part of a mould. 
 
 54 
 
WHERE THE LOCOMOTIVES ARE MADE 
 
 In a similar manner he makes a top part, which 
 when put together with the bottom one will form a 
 complete mould. Suitable locating pegs and holes 
 ensure that the depressions in the bottom part shall 
 eventually correspond exactly with the depressions 
 in the top part, so that when the cavities so formed 
 are filled with metal the result will be a complete 
 brake block. 
 
 In the course of this operation he cuts holes and 
 channels in the sand with a trowel, through which to 
 pour the iron, and finally he clamps the boxes together 
 in order to prevent the possibility of the top one 
 floating when the metal is poured in. 
 
 In other parts of the foundry we see other moulds 
 being made, some very much larger and more com- 
 plicated, but they are all done on the same principle. 
 
 Suddenly a warning shout makes us turn our heads 
 to find the travelling crane hurrying along the shop 
 carrying a large ladle, like a gigantic bucket. As it 
 approaches us we feel that it is intensely hot, and a 
 nearer view reveals that the inside is bright red with 
 heat. It has just poured its recent load of molten 
 iron into a mould and is returning to the furnace for 
 more. Suppose we follow it. 
 
 The furnace is outside the building, but a spout 
 projects through the wall, and just as we arrive we 
 see a man chip out a little plug of clay which till 
 then had sealed a small hole at the far end of the 
 spout. Instantly a stream of white-hot liquid com- 
 mences to trickle down the spout and pour into the 
 ladle waiting to receive it. 
 
 While waiting for it to be filled we can notice this 
 
 55 
 
WHERE THE LOCOMOTIVES ARE MADE 
 
 ladle. It is made of steel plates riveted together 
 like a boiler, but, inside it, is a thick lining which 
 our guide tells us is made of sand. The sand is 
 made into a sort of mortar and spread on, then a 
 fire is made inside to dry it and bake it hard, after 
 which it is ready for use. The lining has to be 
 renewed daily. 
 
 The ladle is now full and the furnace man seals 
 the " tapping hole " once more, the crane hurries 
 off with the full ladle, and if we wish to see the 
 moulds filled we, too, must hurry. On reaching where 
 the mould lies we see the ladle being tipped by one 
 man, while another with a long rod clears the dross 
 from off the top of the metal ; a third meanwhile 
 stirs the metal and others stand around in case of 
 need. Altogether, the pouring of a big casting is 
 an exciting as well as a picturesque and, it may be 
 added, a warm undertaking. 
 
 Leaving the foundry, since time is getting on, we 
 just glance at the tall, steel tube standing vertically 
 outside the foundry which constitutes the furnace 
 or " cupola," to give it its professional name. It is 
 about 5 ft. in diameter and as high as a two story 
 house. Composed of steel plates riveted together, 
 it has a lining of fire-brick, while near the bottom it 
 is encircled by a hollow belt through which air is 
 blown into the fire, the compressed air being derived 
 from a fan or blower in a smaller house near by. 
 
 Coke and pig iron are fed in through a hole near 
 the top, the men working upon a stage placed high 
 up for the purpose. 
 
 In the brass foundry, which we visit next, the 
 
 56 
 
w 
 
 8 I 8 
 
 t;i 
 
 PQ S <" 
 
 -u **> 
 
 a 5 
 
 ."S rt 
 
 rt j= -M 
 
 c H u 
 

WHERE THE LOCOMOTIVES ARE MADE 
 
 metal is melted in crucibles in furnaces beneath the 
 floor. The moulds are made in a similar way and 
 are filled from the crucibles, which are lifted out 
 bodily and carried in a kind of cradle by two men. 
 
 When the castings have cooled, the moulds are 
 broken and the rough castings are pulled out. In 
 the case of iron they are dressed with wire brushes 
 to get the sand off, and little excrescences are cut 
 off with a hammer and chisel, a process called 
 "fettling." The "runners," too, the metal which 
 remained in the channels formed to pour the iron 
 through, are cut off usually with a chisel. 
 
 Brass castings, being of a softer nature, are some- 
 times treated differently. Here, as we pass on our 
 tour, we see a sand-blast chamber, a cabin built of 
 steel plates with a little window through which we 
 can look. There we see a man in a dress something 
 like that of a diver, holding in his hand a tool like 
 a pistol at the end of a pipe. He points the " pistol " 
 at a rough brass casting and lo ! it becomes almost 
 instantly clean over a considerable patch opposite 
 the muzzle. As he moves the tool about the clean 
 patch spreads until the thing is soon clean all 
 over. 
 
 Having finished, he lays down his " weapon," 
 takes off his helmet and opens the door of his prison. 
 Looking through the door we can now see more of 
 the apparatus. 
 
 He wears a helmet to keep the dust from his 
 lungs. The pistol is supplied with compressed air 
 from a machine just outside the cabin, and the 
 jet of compressed air carries with it innumerable 
 
 57 
 
WHERE THE LOCOMOTIVES ARE MADE 
 
 little pellets of iron, called " chilled iron shot." It 
 is this jet of air, reinforced by the shot, which so 
 quickly cleans the castings. The shot, having done 
 its work, falls on the floor, drops through the tiny 
 perforations with which the floor is pierced and is 
 sucked away to be used over again. 
 
 Close by another strange machine demands our 
 attention. Before it there stands a man with a 
 brass casting in his hand just as it came out of the 
 sand, with the " runner " adhering to it. He inserts 
 this between two teeth with which the machine is 
 armed, presses a pedal and in a second the teeth 
 come together and bite off the runner just as a boy 
 bites a piece of cake. 
 
 Lastly we reach the crowning experience of all, 
 the shop where the engines are erected, where the 
 parts from all the other shops come together and are 
 combined into the wonderful machines which draw 
 the trains along. 
 
 It is a large and lofty shop with the inevitable 
 electric crane overhead. Running lengthwise of the 
 shop are many pairs of rails, all of which merge 
 together into one at one end. Between the rails 
 are the " pits " over which the engines are put 
 together, and in which the men can stand when they 
 need to work at the underneath side of the engines. 
 
 First the framework is built up, being supported 
 upon screw jacks. Then the cylinders are put in 
 place and many other less important parts, then the 
 frame is lifted by the crane, the jacks taken away 
 and the wheels run underneath. Then the boiler 
 is lifted on to the frame and properly fitted to it, 
 
 58 
 
WHERE THE LOCOMOTIVES ARE MADE 
 
 and thus the engine grows bit by bit until it is ready 
 to go forth for its trials. 
 
 There is little machinery in this shop. The final 
 assembling together has to be done very largely by 
 human agency, for after all the human frame is the 
 most adaptable machine in existence. For varied 
 and delicate work the human fingers and hands are 
 supreme. 
 
 So there we have an impression, necessarily a very 
 superficial one, of a stroll through a locomotive 
 works. A whole book could be devoted to it, for 
 there are many things not even mentioned in this 
 description, but a general idea is always of value, 
 since it can be added to and the spaces filled in as 
 we add to our store of knowledge. 
 
 59 
 
CHAPTER IV 
 HOW A LOCOMOTIVE WORKS 
 
 THERE is no doubt that the most fascinating 
 feature of the railway is the steam loco- 
 motive. There is something almost human 
 about it. Few sights are more impressive than the 
 slow, dignified entry of a big engine, with a heavy 
 train behind it, as it draws up in a terminus after a 
 long run. One almost feels a desire to pat it on the 
 back as one would do to a friend who had accom- 
 plished an athletic feat with credit to himself and 
 his associates. 
 
 Now how does this wonderful machine work ? 
 To the casual observer it looks very mysterious 
 and difficult to understand, but if we take it a 
 part at a time we shall find that it is really very 
 simple. 
 
 Let us start with the boiler. When we look upon 
 what we deem to be the boiler of a locomotive we 
 are, in fact, merely looking at the covering which 
 is put around the real boiler for the purpose in- 
 cidentally of making it look nice, but chiefly to keep 
 the heat in. The boiler itself is really a rather ugly 
 structure of steel plates with unsightly seams and 
 studded with rivet-heads. Around that is placed a 
 layer of non-conducting composition, then a layer 
 
 Q 
 
HOW A LOCOMOTIVE WORKS 
 
 of wood laths and finally a coat of smooth sheet 
 iron, which last is made beautiful by skilful 
 painting. 
 
 The boiler itself is cylindrical, but it is supported 
 at each end in a kind of box, the front one being the 
 smoke-box and the hind one the fire-box. 
 
 The ends of the boiler are closed by steel plates 
 perforated by a number of holes into which tubes 
 
 FIRE 
 BOX v 
 
 FIRE BARS 
 
 FORMING 
 
 HEARTH 
 
 0> 
 
 END OF 
 STEAM PIPE 
 
 Boiler Proper 
 
 END OF BLAST 
 PIPE 
 
 SMOKE BOX 
 
 TUBES THROUGH WHICH PASS HOT 
 CASES FROM FfRE 
 
 Fig. 1. 
 
 This diagram is intended to give a general idea of the internal 
 construction of the boiler of a locomotive * 
 
 are fitted, each tube running straight through from 
 fire-box to smoke-box. 
 
 The flames and hot gases from the fire in the fire- 
 box thus pass through the tubes into the smoke-box, 
 and in doing so heat the water which surrounds the 
 tubes. The purpose of this form of construction 
 is to obtain as large an area as possible through 
 
 * Wherever the word "diagram" is used in connection with an 
 illustration, it should be clearly understood that the drawing is 
 not an exact representation of the object. 
 
 It is probably not to scale and certain details may be left out 
 and others modified. This is done in order that the general principle 
 of the thing may stand out clearly. 
 
 61 
 
HOW A LOCOMOTIVE WORKS 
 
 which heat can pass from the hot gases into the 
 water. In stationary boilers this result is attained 
 in a different way, but this is the best way to do it 
 in the limited space available on a locomotive. 
 
 It may be mentioned in passing that there are a 
 lot of things which the locomotive engineer would 
 like to do differently, but he is prevented by the 
 limitations of size. 
 
 The fire-box is itself made double, like one box 
 inside another, so that the inner box which contains 
 the fire is practically surrounded by water which is 
 in free communication with the water in the boiler 
 proper. This, again, is to obtain greater heating 
 surface. 
 
 There is a furnace inside this inner shell of the 
 fire-box with a floor of fire-bars, upon which rests 
 the fire from which the whole energy of the engine 
 comes. 
 
 The boiler of a locomotive is really too small for 
 its work. It would be better if there were more 
 space in it for the storage of steam. In other words, 
 it works more nearly full of water than is desirable, 
 and one of the results of this is that steam taken 
 from the upper part of it is " wet," which means that 
 it contains a lot of tiny globules of water and is not 
 pure steam. These globules tend to fill the cylinder 
 with water and prevent it working properly, a fact 
 which gives rise to the use of a steam dome, that 
 familiar feature on the back, so to speak, of most 
 locomotives. 
 
 The dome is a kind of excrescence growing out of 
 the boiler, and the pipe through which the steam is 
 
 62 
 
HOW A LOCOMOTIVE WORKS 
 
 drawn out has its open end right up inside this, as 
 high above the surface of the water as possible. The 
 higher a point is above the water the less water 
 particles are there, and consequently this pipe 
 obtains the steam in the dryest possible condition. 
 
 Entering the open end of the eduction or " leading 
 out " pipe, the steam flows down and then along, 
 by the most convenient route, to the cylinders, 
 passing on its way the regulator valve by which the 
 whole w r ork of the engine is controlled. This valve 
 is so placed that a rod can conveniently pass to the 
 cab where the driver is, and upon the end of this 
 rod is the familiar handle or " regulator " by means 
 of which the driver can start, stop and regulate the 
 speed. 
 
 In the cab there are a number of other devices 
 besides the regulator, the most important of which 
 are the pressure gauge and the gauge glass. 
 
 The pressure gauge is in appearance like a clock 
 with one hand. The figures round the dial represent 
 " pounds per square inch," and thus the position of 
 the hand tells the driver at any moment what is the 
 pressure of the steam in his boiler. It is able to tell 
 him this because it is connected by means of a tube 
 to the interior of the boiler itself. It is itself of a 
 wonderfully simple construction, there being little 
 inside the case except a bent tube sealed at one end, 
 but in communication with the boiler at the other. 
 Fluid pressure inside a bent tube tends to straighten 
 it, and so as the pressure rises the bent tube more 
 and more straightens itself, which movement is made 
 to turn the hand. 
 
 63 
 
HOW A LOCOMOTIVE WORKS 
 
 If you notice carefully you will see that this gauge 
 generally surmounts another bent tube, this one 
 being on the outside. The purpose of this is to protect 
 
 STEAM ENTERS 
 
 Fig. 2. How THE STEAM REACHES THE CYLINDER, 
 
 With the slide valve in the position shown, the staam finds 
 the right-hand port open, and passing through it enters the 
 right-hand end of the cylinder and pushes the piston towards 
 the left. 
 
 Meanwhile, the steam left in after the previous stroke is 
 pushed out through the left-hand port and led to the centre 
 port, through which it escapes to the chimney. 
 
 As the piston is moved by the steam it in turn moves the 
 slide valve until it reaches the position shown dotted. The 
 whole operation is then reversed and the piston is pushed back. 
 
 All parts are here shown as if cut in half, and the rod that 
 moves the valve is left out altogether. 
 
 the gauge from the effects of the varying temperature 
 of the steam ; the water which quickly collects in 
 the curl of this tube maintains a fairly even tem- 
 perature, so that it shields the gauge from these 
 
 64 
 
HOW A LOCOMOTIVE WORKS 
 
 variations, yet it transmits the changes in pressure 
 very readily. 
 
 The gauge glass is a vertical tube of glass carried 
 in brass fittings which are in communication with 
 the interior of the boiler, so that as the level of the 
 water rises and falls in the boiler it does the same in 
 the tube, and by looking at the tube the driver can 
 see at any moment what is the level of the water 
 inside. 
 
 Let us now turn our attention to the " smoke-box " 
 at the other end. The hot gases from the fire, and 
 the smoke when there is any, come through the 
 tubes into the smoke-box and then find their way up 
 the chimney, which is really a continuation upwards 
 of the smoke-box itself. 
 
 In addition to this there is a pipe with an open 
 end standing up vertically precisely under the 
 chimney. This is the " blast-pipe," and is one of 
 the most important features of the engine. It was 
 the invention of the " blast -pipe " by George 
 Stephenson which more than anything else made the 
 locomotive a success. 
 
 Through this pipe comes the " exhaust steam " 
 from the cylinders. If the locomotive were a per- 
 fectly efficient engine this steam would have little 
 or no force in it, but, in fact, it shoots up from the 
 " blast-pipe " with a very considerable force, and 
 in so doing creates a strong draught up the chimney. 
 This sucks the gases through the tubes and so draws 
 air into the furnace, causing the fire to burn strongly 
 and enabling steam to be kept up. In the early 
 engines it was found almost impossible to maintain 
 E 65 
 
HOW A LOCOMOTIVE WORKS 
 
 the supply of steam from a boiler really too small 
 for its work, but the happy idea of blowing the exhaust 
 steam up the chimney in this way solved the diffi- 
 culty completely. 
 
 The blast is, of course, only at work when the 
 engine is running, so it is reinforced by a smaller 
 pipe of a similar kind, called the " blower," by which, 
 when the engine is at rest, the driver can direct a 
 jet of steam straight from the boiler up the chimney 
 to do the work of the blast. The steam jet is con- 
 trolled by a handle in the cab. 
 
 So much for the boiler ; let us now turn our atten- 
 tion to the " engine " proper. 
 
 The most important part is, of course, the cylinder, 
 a box made of cast iron, the inside truly cylindrical 
 and smooth, in which there slides to and fro a second 
 cylindrical object called the " piston." The steam 
 enters first at one end and then at the other, thereby 
 pushing the piston from end to end, first one way 
 and then the other. A rod, called the " piston-rod," 
 communicates this motion through one of the 
 " covers " of the cylinder to the crank. 
 
 That brings us to the most important part of all, 
 the valve which automatically distributes the steam 
 to the two ends alternately and at the same time 
 liberates the old steam which has done its work. 
 It is called a " slide valve " because its mode of work 
 is to slide backwards and forwards upon a smooth 
 surface. 
 
 This surface, which is termed the " valve face," 
 is formed on one side of the cylinder casting. A box- 
 like part is inverted over the valve face so that the 
 
 66 
 
HOW A LOCOMOTIVE WORKS 
 
 face forms, as it were, the floor of a rectangular 
 chamber, called the " steam chest." The steam 
 enters the " steam chest " through an orifice made 
 for the purpose and thence passes to the " ports," 
 passages formed in the walls of the cylinder which 
 terminate in holes in the steam chest. 
 
 There is one hole from which a port leads to one 
 end of the cylinder and another hole whence a port 
 leads to the other end. In between these is a third 
 hole which is really the entrance to the " exhaust 
 port," a passage leading out of the cylinder altogether. 
 
 Were there nothing more than this, then, steam 
 entering the steam chest would pass, some to one 
 end of the cylinder, some to the other, while some 
 would escape altogether. 
 
 The valve, however, changes all this. It is like a 
 lidless box placed open end downwards upon the 
 valve face. Assuming it to be at one end steam 
 entering the steam chest finds two of the holes 
 covered, so that it can only pass to one end of the 
 cylinder. It, therefore, will push the piston to the 
 other end. Suppose now that the slide valve be 
 also pushed to the other end. The port throngh 
 which the steam has just gone in will be closed aud 
 the other one uncovered. Steam will now enter at 
 the opposite end and the piston will be pushed back 
 again. 
 
 But what will happen to the first lot of steam that 
 went in ? It will come out through the same port 
 by which it entered, but this time it will go into the 
 inside of the slide valve. Now the slide valve is so 
 arranged that the centre port, that which leads to 
 
 67 
 
HOW A LOCOMOTIVE WORKS 
 
 the open air, is always open to the inside of the valve. 
 Consequently, as the old steam comes out from the 
 port into the inside of the valve, it finds a ready 
 means of escape through the " exhaust port." 
 
 To put it another way, the action of the slide 
 valve is to uncover one steam port and to connect 
 the other one to the exhaust port, and this it does 
 at the two ends alternately. If this description is 
 not clear a glance at the diagram on page 64 will 
 be of material assistance. It is worth a little trouble 
 to get a thorough understanding of this, the most 
 essential part of every steam engine. 
 
 In some of the most modern engines the simple 
 slide valve gives place to a " piston valve," the form 
 of which is slightly different, although the principle 
 is the same. The piston valve consists of two pistons 
 connected by a rod working in a small cylinder 
 alongside the main cylinder. 
 
 In all these parts " steam-tightness " is the great 
 thing to be sought after. The piston needs to slide 
 freely in the cylinder, but it must not allow any 
 steam to slip past, and it seems at first sight that if 
 the piston be loose enough to move freely steam will 
 inevitably get past it. Or to put it the other way, 
 if it be tight enough to prevent the passage of steam 
 (for we know what a slight crack steam can get 
 through) it must be too tight to move freely. 
 
 This apparent dilemma is avoided in this simple 
 way. The piston is made quite a loose fit in the 
 cylinder, but around its edge is turned a groove, and 
 in this groove there fit a number of spring rings. 
 These rings spring outwards, so that they keep up a 
 
 68 
 
HOWjV LOCOMOTIVE WORKS 
 
 gentle pressure upon the cylinder walls, making a 
 perfect joint against them, past which no steam can 
 escape, yet their pressure is so slight that they do 
 not interfere in any way with the free movement of 
 the piston. 
 
 The slide valve is made steam-tight in an even more 
 simple manner. The valve face is planed flat and 
 smooth, and so is the face of the valve which comes 
 into contact with it. Then each one is rubbed with 
 a flat piece of steel on which has been smeared some 
 red paint. This at once reveals any slight irregu- 
 larities, which are forthwith removed by scraping 
 by hand. A careful workman can soon make the 
 two surfaces so flat that no steam can pass between. 
 
 The outer end of the piston rod terminates in the 
 " cross-head," a block of steel which slides to and 
 fro between a pair of guides. To this is pivoted one 
 end of the " connecting rod," the other end of which 
 grasps the " crank " which is formed upon the axle 
 of the driving wheels, or in some cases upon the driving 
 wheel itself. 
 
 Thus, as the piston moves to and fro, its motion 
 is communicated to the cross-head, and that again 
 is changed by the connecting rod and crank into 
 the round and round motion of the wheels. 
 
 The next question that presents itself is, how is 
 an engine reversed ? 
 
 To answer that we must first see how the valve is 
 moved. It is clear that the working of the valve 
 must be automatic, and the simplest thing would 
 seem to be to connect it with the piston rod. The 
 difficulty arises there, however, that the valve needs 
 
 69 
 
HOW A LOCOMOTIVE WORKS 
 
 to be in the middle of its stroke just when the piston 
 is at one end. A study of the diagram on page 64 
 will show why this is so. 
 
 A simple way to do it would be to put an extra 
 crank upon the main axle at right angles to the main 
 crank, and to connect that crank by means of two 
 rods, similar to the connecting rod and the piston 
 rod, to the valve. That is, in effect, what is done, 
 but instead of a second crank an eccentric is generally 
 employed. This is a round disc mounted upon the 
 shaft by means of a hole out of its centre. A strap, 
 called the eccentric strap, encircles this, and this 
 strap is connected by the " eccentric rod " to the 
 valve rod. Thus as the eccentric " wobbles " round 
 inside the strap it gives a to-and-fro motion to the 
 valve just as a crank would do. An eccentric rod is 
 for practical reasons preferred to a crank ; it takes 
 up less room on the axle and does not weaken it at 
 all as a crank does. 
 
 In some engines, particularly where the cylinders 
 are on the outside of the frame, this arrangement is 
 for practical reasons impossible, and in such cases 
 an ingenious series of levers is made to produce the 
 same result. 
 
 And now we can see how to reverse the engine. 
 As we have seen from the diagram on page 64, 
 let us imagine the slide valve in the middle position. 
 If the valve then moves to the right the piston will 
 follow it in the same direction. If it moves to the 
 left the piston will also move to the left. Thus to 
 reverse the direction of the engine all we need to do 
 is to reverse the action of the slide valve. 
 
 70 
 
 
HOW A LOCOMOTIVE WORKS 
 
 Imagine, therefore, two eccentrics set upon the 
 axle side by side, but with their big sides opposite 
 to each other. There will be two straps and two 
 eccentric rods, and as the axle turns one rod will 
 always be pulling as the other is pushing. Now let 
 these two rods terminate in a " link " something 
 
 REVERSING 
 ROD 
 
 C CENTRIC 
 
 THIS WORKS 
 
 UP AND 
 DOWN IN LINK 
 
 Fig. 3. How AN ENGINE is REVERSED. 
 
 (Suppose that the two axles are so connected that they 
 turn as one.) 
 
 The two eccentrics cause the link to rock like a see -saw. Aa 
 shown above, therefore, the valve will not be worked at all, 
 because its rod is connected to the centre of the link. 
 
 If the reversing rod be pulled, the link will move upwards 
 and the valve will come under the control of the lower eccen- 
 tric. Likewise, if lowered, the upper eccentric will take control. 
 Since the eccentrics are set opposite each other, the action of 
 the valve is thus reversed. 
 
 N.B. In practice the two eccentrics are set side by side 
 upon the same axle. 
 
 like an elongated chain-link, only made smooth and 
 nicely finished. One rod is attached to each end of 
 the link, and the result is that the motion of the 
 link is like that of a see-saw, the two ends always 
 moving in opposite directions. The valve rod is 
 furnished with a pin which fits into the slot in the 
 link, and there are a series of rods and levers by 
 
HOW A LOCOMOTIVE WORKS 
 
 which the link can be raised and lowered so that 
 either eccentric can, at will, be made to work the 
 valve. When the link is up one eccentric will work 
 it ; when it is down the other. 
 
 Assuming, then, for the sake of simplicity, that the 
 engine has stopped with the piston in the middle of 
 the cylinder. Which way the engine will start will 
 depend entirely upon which eccentric is put in 
 control of the valve. 
 
 The engine need not, in fact, be in that precise 
 position, for sliding the link up or down will at any 
 time cause the action to be reversed. 
 
 This is the " link-motion " reversing gear, invented 
 by George Stephenson and scarcely altered since 
 his time. The link, of course, is moved up or down 
 by the action of the lever or screw in the cab, and so 
 the driver can control the direction of movement 
 of his engine. 
 
 Every locomotive has at least two cylinders, 
 and each of them works on to a separate crank. 
 The two cranks, moreover, are set at right angles. 
 The reason of this is that a single cylinder can best 
 exert its power when the crank is in one position, 
 namely, at right angles to the direction of the piston 
 rod or thereabouts. As it gets more and more in 
 line with the piston rod it loses leverage, and there 
 is one position of the crank where the piston has no 
 turning power at all. If the cranks were set opposite 
 to each other this position of powerlessness would 
 occur at the same moment for both of them, but 
 when at right angles one is at its best just when the 
 other is at its weakest, so that the combined action 
 
 72 
 
HOW A LOCOMOTIVE WORKS 
 
 of the two is uniform and, moreover, the engine can 
 start equally well from all positions. 
 
 A few engines have three cylinders and some have 
 four. In some cases, even of four-cylinder engines, 
 the steam goes direct from the boiler to all of them, 
 but in others, called " compound " engines, the 
 steam after leaving the first two goes either to one 
 other, very large, one, or else to two others. The 
 advantage of this it would be well to explain, but 
 that we will save for another chapter. 
 
 Engines possess three types of wheels. The most 
 important are the driving wheels, which are actually 
 turned round by the mechanism and which by 
 gripping the rails propel the train along. These 
 are generally near the centre of the engine, and there 
 are frequently others before and behind, wheels 
 which simply help to carry the weight and 
 take no part in hauling the load. These are 
 spoken of respectively as " leading " and " trailing " 
 wheels. 
 
 It is by the numbers of these wheels that the type 
 of engine can be described. It seems strange to sum 
 up the characteristics of an engine by means of one 
 feature, but these are so fundamental that you need 
 only tell an experienced man the number of wheels 
 of these three types for him to gather a very good 
 general idea of any particular engine. 
 
 Thus if we call an engine a 4-4-0 we mean that it 
 has four leading wheels, four driving wheels, and 
 no trailing wheels. If we say 0-4-2 we mean that 
 it has no leading wheels, but that it has four 
 driving wheels and two trailing wheels. 
 
 73 
 
HOW A LOCOMOTIVE WORKS 
 
 Generally the power from the pistons is communi- 
 cated directly to cranks upon the axle of one 
 pair of driving wheels, and the other driving 
 wheels are coupled to the first pair by the " side- 
 rods " which are such a familiar feature of loco- 
 motives. 
 
 There are cases, however, of engines with more 
 than one pair of cylinders, where one pair drive one 
 pair of driving wheels and the other or others drive 
 another pair of wheels. However that may be, 
 there are always side-rods to ensure that all driving 
 wheels shall pull together, except in that dying class 
 of fast passenger engines where only a single pair of 
 driving wheels exist. 
 
 Another question which the enquiring mind may 
 raise is how is the boiler supplied with water ? Is 
 it pumped ? 
 
 An injector is used for this purpose. As the name 
 implies this throws the water in. It does not push 
 it in like a pump does, but actually throws it. It 
 is one of the strangest of appliances, for in it a jet 
 of steam forces the water into the boiler against the 
 same pressure of steam trying to drive it out. In 
 other words, two equal pressures meet, yet in spite 
 of their equality one seems to overpower the other. 
 Briefly the arrangement is this : a jet of steam issues 
 from a nozzle and enters a funnel which is placed 
 exactly opposite to it ; around the nozzle is water 
 which the jet carries forward and to which it imparts 
 such a high velocity that it is thrown into the boiler 
 in spite of the pressure in the boiler which tends to 
 keep it out. The action of this is very simple, and 
 
 74 
 
HOW A LOCOMOTIVE WORKS 
 
 is specially suited to the work required of it on a 
 locomotive. 
 
 The water is carried in a tank in the tender, in 
 the case of those engines which have tenders, or in 
 the case of those without, in a tank or tanks on the 
 engine itself. That is why engines without tenders 
 are termed " tank " engines. 
 
 Frequently there are three types of brake in use. 
 The engine itself has a steam break in which steam 
 in a cylinder moves a piston to which is connected 
 the brake gear. When the piston moves it therefore 
 presses the brake blocks against the wheels. The 
 tender usually has a hand brake which is applied 
 by the fireman turning a handle. Finally, the engine 
 carries the apparatus for working the " continuous " 
 brake on all the vehicles of a passenger train. 
 
 All engines are thus fitted, even those intended for 
 goods traffic, since even they may at times be called 
 upon to work passenger trains. In many cases, too, 
 they are fitted for both kinds of continuous brake, 
 so that they can work whichever type their train 
 may happen to possess. 
 
 In conclusion, just one word about the way in 
 which engines are adapted for the various kinds of 
 work. 
 
 A goods engine needs to be able to pull heavy 
 loads at moderate speeds. Hence it has plenty of 
 driving wheels coupled together, to give it plenty 
 of tractive power. Six driving wheels is very usual 
 and sometimes eight. The driving wheels are, how- 
 ever, relatively small, since the smaller they are the 
 more easy is it for the mechanism to turn them. 
 
 75 
 
HOW A LOCOMOTIVE WORKS 
 
 Passenger engines, having to handle lighter loads 
 at higher speeds, usually have no more than four 
 wheels coupled, and the diameter is larger. To run 
 at a high speed the smaller wheels of the goods type 
 would have to turn too fast for the welfare of the 
 mechanism, hence for fast traffic larger wheels are 
 preferred. 
 
 Long journeys without stops call for tender engines 
 because of the quantity of water needed. On the 
 contrary, when frequent stops do not matter it is 
 an easy thing to pick up water at wayside stations, 
 so that for stopping trains tank engines are the 
 rule. 
 
 Likewise, for heavy traffic on heavy roads, that is 
 to say hilly roads, the engines have to be, generally 
 speaking, of a heavier type than those in use on 
 level roads where also the traffic happens to be 
 light. 
 
 It is all these considerations which account for 
 the various kinds of engines to be found on different 
 lines. Each line has developed the types calculated 
 to deal with the traffic most effectively under the 
 conditions which prevail upon that line. 
 
CHAPTER V 
 COMPOUND LOCOMOTIVES 
 
 familiar " puffing " of the locomotive is 
 a sign that good, useful energy is going to 
 waste. If the locomotive were more perfect 
 the steam would escape from the chimney just like 
 that from a lightly boiling kettle, without any force 
 at all. 
 
 As we have seen already, a part of this energy is 
 made to do the useful work of fanning the fire, 
 thereby making it burn well, and so remedying one, 
 at least, of the weaknesses inherent in the loco- 
 motive. Still, even when that has been allowed for 
 a great deal of waste takes place. 
 
 To understand this we need to realize that steam 
 under pressure is like a coiled-up spring. Just coil 
 up a stout clock spring, by way of illustration, and 
 tie it with string. As it lies upon a table it looks 
 quite feeble and without energy, but cut the string 
 and it will fly out with force enough to give you 
 a nasty blow should it strike you. 
 
 Now when you turn on the steam to a steam engine 
 it finds its way, as already described, through the 
 various pipes into the steam chest, then through 
 one of the ports into the cylinder, where it pushes 
 the piston from one end of the cylinder to the other. 
 
 77 
 
COMPOUND LOCOMOTIVES 
 
 The pressure of steam in the boiler when the valve 
 was opened was, let us say for the sake of example, 
 150 Ibs. per square inch. When we let some out 
 into the steam pipes and cylinder the pressure tends 
 to fall, but that is prevented by the fact that more 
 and more steam is being continually given off by 
 the water in the boiler. We arrive at the fact, 
 therefore, that boiler, pipes and cylinder are all full 
 of steam at 150 Ibs. per square inch pressure. Let 
 us now close the valve, so that no more steam can 
 enter ; we then have a cylinder full of steam at 
 150 Ibs., and it is like the coiled-up spring, because 
 if we let it out it will expand to about ten times its 
 present volume. Or, to put it another way, if we 
 could, by a miracle, elongate the cylinder to about 
 ten times its present length, the steam already in, 
 without any further help from outside, could push 
 the piston to the further end. In other words, when 
 we fill the cylinder with steam at boiler pressure the 
 steam has still a great deal of force left in it after it 
 has pushed the piston the length of the cylinder. 
 We will call this the " expansive force " of the steam. 
 
 And now, please, carry your thoughts back to the 
 description of the steam locomotive and its reversing 
 gear. You will remember that it is reversed by the 
 use of two eccentrics, each of which operates one 
 end of a link ; the two eccentrics are set opposite, 
 so that the link rocks like a see-saw and by moving 
 the link up or down, as the case may be, either end 
 can be made to work the slide valve. 
 
 Thus the centre of the link does not move at all. If, 
 then, we raise the link slowly, as the engine is at 
 
 78 
 
COMPOUND LOCOMOTIVES 
 
 work, the slide valve is moved less and less until, 
 when the link is in mid-position, it is not worked at 
 all ; then, if we continue, the amount of movement 
 increases again until it is once more moving to its 
 full extent. So, by raising or lowering the link we 
 can vary the stroke of the slide valve. 
 
 In actual practice this is done and by it a good 
 deal of saving is effected. The reversing lever works, 
 as you have probably noticed, between guides 
 shaped like a quadrant, and in the quadrant are 
 notches into which a catch engages, so that the 
 driver can fix it in any one of a number of positions. 
 As the engine is running the driver " notches it up," 
 as he expresses it, meaning thereby that he moves 
 his reversing lever more and more towards its central 
 position. If he put it in the central position he would, 
 of course, stop his engine altogether, since in that 
 position the slide valve remains still, so what is the 
 purpose of this operation ? 
 
 We have seen that after filling the cylinder with 
 steam there is still enough force left in the steam to 
 propel the piston about ten times as far. Suppose, 
 then, that we only put into the cylinder enough 
 steam to half-fill it ; the expansive force will push 
 the piston the other half. We shall thereby reduce 
 our steam consumption by half, but the power 
 generated by the engine, while less than if we had 
 filled the cylinder, will be reduced by much less than 
 half, so that on balance our engine becomes more 
 efficient. To carry the idea further, if we cut off 
 the supply of steam when the cylinder is only a 
 quarter full we shall get three-fourths of the stroke 
 
 79 
 
COMPOUND LOCOMOTIVES 
 
 done by the expansive energy of the steam, and 
 so on. 
 
 When new steam is entering the cylinder it pushes 
 with practically the full boiler pressure all the time, 
 but when the steam is working by expansion its 
 pressure falls rapidly. Consequently, when starting, 
 or when struggling against a very heavy load, the 
 steam may be admitted during practically the whole 
 stroke, but when the train is under way and the 
 full tractive power of the engine is not required, the 
 driver saves steam, and therefore coal, by working 
 as much as he possibly can on the expansion of the 
 steam. 
 
 There is a limit, however, to the amount of ex- 
 pansion which can be used in a single cylinder. As 
 the steam expands it cools rapidly and so chills the 
 cylinder at that end where the next lot of steam 
 will enter. Thus if the expansion be carried too far 
 the steam which enters for the next stroke will be 
 partially condensed by the cool walls of the cylinder 
 and power will thereby be lost. 
 
 This is partly obviated in some of the most modern 
 locomotives by " super-heating " the steam. It 
 should be understood that it takes a certain tem- 
 perature to convert water into steam at any given 
 pressure. As the pressure rises the temperature of 
 the steam rises too, so that for every pressure there 
 is a corresponding temperature. We might call 
 this the " natural " temperature corresponding to 
 the pressure. But we can take a quantity of steam 
 at its " natural " temperature and heat it further. 
 We can, in fact, heat steam just as we can heat air 
 
 80 
 
COMPOUND LOCOMOTIVES 
 
 or any other vapour. This added heat, over and 
 above the " natural " temperature, we call " super- 
 heat." Its chief value in the working of steam 
 engines is that steam when super-heated has a 
 surplus of heat which it can part with before con- 
 densation commences. 
 
 Suppose you take a quantity of steam at its 
 " natural " temperature, and introduce it into a 
 cylinder cooler than itself, a considerable part of it 
 will immediately condense and the pressure will fall 
 rapidly. If, however, it is super-heated, it will not 
 begin to condense until all the super-heat has gone. 
 
 By suitable arrangements the super-heat can be 
 obtained free, by utilizing heat which would other- 
 wise go to waste. 
 
 A super-heater locomotive has in its smoke-box a 
 number of tubes through which the steam passes 
 on its way from the boiler to the cylinders. This 
 arrangement of tubes is called a " super-heater," 
 and it is so placed that the hot gases after passing 
 through the tubes of the boiler strike against it before 
 making their way upwards to the chimney. Thus 
 heat which would otherwise be carried away into 
 the air is imparted to the steam on its way to the 
 cylinders, and so it becomes " super-heated." 
 
 To accommodate the super-heater the smoke-box 
 generally has to be enlarged a little, with the result 
 that a " super-heater " locomotive can usually be 
 recognized from the fact that its smoke-box is 
 obviously longer than is generally the case. 
 
 While on the subject of condensation another 
 little point may be mentioned here, although it is 
 F 81 
 
COMPOUND LOCOMOTIVES 
 
 not strictly connected with the subject of this 
 chapter. At starting, when the cylinders are com- 
 paratively cool, there is a great tendency for some 
 of the steam to condense in the cylinders, and if it 
 were to be allowed to accumulate it might have very 
 disastrous effects. Water is only compressible to a 
 very slight extent, so that if there were more water 
 in a cylinder than would fill the small space between 
 the end of the cylinder and the furthest point in 
 the travel of the piston something would have to 
 " go." In all probability the cylinder-cover would 
 be knocked right off and one end of the cylinder 
 left quite open. 
 
 To prevent this there is at each end of the cylinder 
 a small tap, called a " drain-cock." These can be 
 operated from the cab by a system of levers, and 
 when he has reason to think that water is collecting 
 the driver opens these and the steam blows it out. 
 That is the cause of the familiar escape of steam 
 under the engine and the harsh hissing sound which 
 accompanies it. 
 
 But to return to our subject ; even when the 
 steam is super-heated it cannot be used expansively 
 in one cylinder beyond a certain extent. Therefore, 
 it is in some cases led to a second cylinder of larger 
 dimensions than the first. 
 
 Probably the question will at once arise in the 
 readers mind, " Why must it be larger ? " Because, 
 in order to obtain the expansive force from the 
 steam we must give it a chance to expand, and it 
 can only expand if we introduce it into a cylinder 
 which is larger than the one it is leaving. 
 
 82 
 
COMPOUND LOCOMOTIVES 
 
 Or we may look at it another way. Imagine the 
 first or " high-pressure " cylinder to be full of steam 
 at, say, 50 Ibs. pressure. We connect it to the "low- 
 pressure " cylinder into which it flows. The low- 
 pressure cylinder, let us suppose, is twice the diameter 
 of the high-pressure, and so as the steam enters it 
 expands and its pressure falls, until at the end of 
 the stroke it is only 25 Ibs. The average pressure in 
 the low-pressure cylinder throughout the stroke will 
 be somewhere about 40 Ibs. 
 
 Now you must remember that the two pistons, 
 the one in the high-pressure cylinder and the one 
 in the low-pressure cylinder, are mechanically con- 
 nected, so that they move together. The high- 
 pressure piston thus pushes the " old " steam out 
 of its cylinder, and the same steam in its turn pushes 
 the low-pressure piston. The high-pressure piston 
 has to exert a pressure of (on the average) 40 Ibs. 
 on every square inch in order to push the old steam 
 out, but because of its expansion that same steam 
 pushes with that same pressure per square inch upon 
 the much larger low-pressure piston. If the area 
 of the high-pressure piston were 100 square inches 
 and that of the low-pressure 200 square inches, the 
 old steam would push back upon the high-pressure 
 piston to the extent of 4000 Ibs., but forward upon 
 the low-pressure to the extent of 8000 Ibs., giving 
 a net gain to the engine of 4000 Ibs. 
 
 One of the earliest of the compound locomotives 
 was a type of engine made and used by the North- 
 Eastern Railway which had two cylinders, one high- 
 pressure and one low-pressure. These were placed 
 
 83 
 
COMPOUND LOCOMOTIVES 
 
 one on each side of the engine, just as are the two 
 cylinders of the ordinary " simple " engine. Had 
 not some provision been made for starting this 
 would have meant that the engine would have 
 started with one cylinder only, for obviously the 
 low-pressure cylinder cannot come into operation 
 till the engine has moved. To overcome this diffi- 
 culty the steam pipes were so arranged that to start 
 the engine steam passed straight from the boiler 
 to both cylinders, so that it started as a " simple " 
 engine. Then, when speed had been attained, the 
 operation of certain valves caused it to change into 
 " compound." 
 
 The London and North-Western Railway, also, 
 were pioneers with a famous type of compound 
 engine in which there were two high-pressure 
 cylinders, one on each side of the engine, and one 
 very large low-pressure cylinder in the centre, between 
 the other two. The two high-pressure cylinders 
 drove one pair of driving wheels and the low-pressure 
 cylinder the other pair, the two pairs being coupled 
 together with side-rods. 
 
 Several British lines have had some compound 
 engines at work for a number of years, and so have 
 some of the United States railways. 
 
 One reason why the compound arrangement is 
 not more generally employed is the oft-mentioned 
 trouble of the limitation of size. To get the best 
 result much more space would be needed than is 
 available upon a locomotive. 
 
 A second reason is the variability of the load, 
 which is at times six or eight times as great as at 
 
 84 
 
COMPOUND LOCOMOTIVES 
 
 others. On ships and in large factories, where the 
 load is fairly steady, steam engines are almost 
 always " compound " or else " triple-expansion " 
 (the steam passing through three cylinders in suc- 
 cession), but in the case of locomotives there are 
 only certain services, where the demand upon the 
 engine is fairly steady, where " compound " engines 
 show to advantage. In other cases the less costly 
 and less complicated " simple " engines will probably 
 continue to hold the field. 
 
 Indeed, the question of " compound versus simple " 
 is such a doubtful one that the building of compound 
 engines is very largely a matter of the personal views 
 of the gentleman who at the moment happens to 
 hold the office of Chief Mechanical Engineer on 
 each line. 
 
CHAPTER VI 
 OIL-DRIVEN LOCOMOTIVES 
 
 FOR industrial purposes the oil engine has made 
 a great place for itself and is a very serious 
 competitor of the steam engine. 
 
 In factories and electric generating stations oil- 
 driven engines are to be found in large and increasing 
 numbers, while for road vehicles the engine worked 
 by a light oil is supreme. The conditions which 
 prevail, however, on a railway have so far left the 
 steam engine in undisputed sway. 
 
 The reasons for this are various. For one thing, 
 the load changes in a manner not to be met with in 
 a factory. For another, the locomotive has to be 
 ready to stop and stait pgain at any moment, whereas 
 in a factory the machinery runs for hours at a stretch. 
 Again, a railway engine must be as near absolute 
 reliability as is possible. 
 
 Now the internal-combustion engine driven by oil 
 is a very wonderful machine, for economy far to be 
 preferred to a steam engine, but it has not the same 
 reliability and it is difficult to see how it ever can 
 have. A steam engine, in bad condition even, will 
 work. It may work badly, but it will go on doing 
 its best until it drops to pieces. There is a steam 
 engine in London driving a factory, which has been 
 
 86 
 
OIL-DRIVEN LOCOMOTIVES 
 
 doing the same thing since before the internal- 
 combustion engine was first invented. The whole 
 history of the gas, oil and petrol engine, from its 
 crude beginning up to the present time, is covered 
 by the working life of that single steam engine. 
 True, it is not very efficient, but it works and the 
 owners of the factory know that they can rely upon 
 it to keep the factory going. 
 
 Nor is that an exceptional case ; it is simply due 
 to the inherent simplicity of the steam engine, a 
 simplicity which applies both to its construction 
 and to its mode of action. 
 
 Against this, consider the short life of the motor- 
 car engine and the fact that even the best motor-car 
 engine, good though it is, has its occasional bad 
 periods when it is reluctant to start, or pulls badly. 
 
 Moreover, internal-combustion engines will only 
 work at a comparatively high speed, whereas a steam 
 engine will work at any speed down to a " crawl." 
 In the motor vehicle this difficulty is mitigated by 
 the use of gearing and in other ways, but those 
 devices cannot be applied practically where such 
 heavy power has to be applied as in the railway 
 engine. 
 
 Then there is the reversing. A steam engine 
 reverses quite easily. The same cannot be said of the 
 internal-combustion engine. 
 
 There was an engine made some years ago in which 
 it was attempted to utilize a steam turbine and so 
 to take advantage of the superior efficiency of the 
 turbine when compared with the ordinary recipro- 
 cating steam engine. But the turbine suffers from 
 
 87 
 
OIL-DRIVEN LOCOMOTIVES 
 
 the same troubles as the internal-combustion engine, 
 in that it only works well at a high speed and cannot 
 be reversed easily. It was, therefore, sought to 
 overcome this by electrical means, and the turbine 
 was made to drive a dynamo at a constant speed 
 and always in the same direction ; while the current 
 from the dynamo was led to motors which drove the 
 wheels. The motors could, of course, be controlled 
 as to speed and direction as they are controlled in 
 every electric train or tramcar. 
 
 The electric machinery, it will be noticed, generated 
 no power at all, as indeed it never does, but simply 
 transmitted the power from the turbine to the wheels, 
 and its only reason for being there at all was to 
 enable the speed and direction to be controlled. 
 
 This engine did not prove a marked success, and 
 there is little reason to expect that any more will be 
 built on those lines. The same method of trans- 
 mission is applicable in connection with an internal- 
 combustion oil engine, but there are many diffi- 
 culties in the way of success. 
 
 At the same time there are many reasons why oil 
 would make an ideal fuel for railway engines. For 
 one thing, it is so clean and easily handled. Instead 
 of the labour of shovelling coal or tipping it into 
 the tender the oil can be pumped in with no trouble 
 and no dust in a small fraction of the time. The 
 fireman, too, on a coal-fired locomotive has to shovel 
 many hundredweights of coal per trip. With oil 
 he has nothing to do but see to the adjustment 
 of two valves, the rest of his energies being available 
 to assist the driver. 
 
 88 
 
^ 5; 
 
OIL-DRIVEN LOCOMOTIVES 
 
 The only solution of the difficulty, therefore, seems 
 to be to burn oil instead of coal in the fire-box of a 
 steam locomotive, and this was actually done in 
 an experimental way for twenty or more years 
 until at last oil obtained a definite place as a fuel 
 for railway steam engines. 
 
 The problem is how to introduce the oil so that it 
 shall burn well and economically. The obvious way 
 is to blow it through a fine nozzle or series of nozzles, 
 so that it shall enter the fire-box in a fine spray. 
 In the earliest experiments the oil was made to 
 combine with a jet of steam in an arrangement of 
 nozzles rather like the " injector " by which the 
 water is driven into the boiler. At first sight it 
 would appear that the mixture of steam with the 
 oil vapour would prevent it from burning or, at all 
 events, damp down the combustion, but experience 
 has shown that such is not the case. The steam, 
 in the hot fire-box, is probably split up into oxygen 
 and hydrogen, the hydrogen acting as additional 
 fuel and the oxygen, being well mingled with it, 
 helping to promote a good combustion of the oil. 
 
 It was the custom, too, in the early trials, to use 
 oil merely as an addition to the coal, some of which 
 was still used. The coal fire burnt upon the fire- 
 bars which form the floor of the fire-box in the usual 
 way, while the steam and oil spray played upon it 
 from above. 
 
 The burning of oil made little progress, however 
 surprisingly little for many years, until necessity, 
 the proverbial " mother of invention," took a hand 
 in the game. 
 
 89 
 
OIL-DRIVEN LOCOMOTIVES 
 
 It came about in this way. During the war, in 
 Mesopotamia, there was a scarcity of any kind of 
 fuel except oil. The locomotives which were being 
 used by the British Army were arranged to burn 
 other kinds of fuel, and so it became a matter of great 
 urgency to devise some arrangement for burning oil. 
 
 Now the great obstacle till then, to the use of 
 oil, had been the idea that the oil must be sprayed 
 through fine nozzles with all the attendant risks 
 that the nozzles, because of their fineness, would 
 frequently choke. 
 
 The petrol used in motor-car engines has to pass 
 through fine holes, and every motorist knows from 
 sad experience how liable these are to be choked 
 with particles of grit, no matter how careful he may 
 be. With the cruder oil used to fire a locomotive 
 this risk would be much greater. 
 
 So there was a dilemma ; the only fuel available was 
 oil, and oil as employed till then was not reliable. 
 
 Fortunately the responsible man, Colonel F. R. 
 Macdonald, was a man of resource, and he was not 
 only able to avoid the dilemma which faced him 
 there, but he provided at the same time a method 
 of burning oil which has been of great value since 
 in all parts of the world. 
 
 To understand the beautiful simplicity and effec- 
 tiveness of this invention, it is necessary just to 
 think what are the points to be attained. First the 
 oil has to be " atomized," that is to say, reduced to 
 the finest possible particles. It cannot, of course, 
 be actually reduced to single " atoms " as the term 
 suggests, but it must be changed into drops of the 
 
 90 
 
OIL-DRIVEN LOCOMOTIVES 
 
 smallest practical dimensions. The second point is 
 that the apparatus must be free from fine nozzles 
 or anything else which would be liable to become 
 choked or otherwise put out of action. It must be 
 something which cannot go wrong. 
 
 We can now see how Colonel Macdonald's " burner " 
 fulfils these two conditions. 
 
 To commence with, imagine a piece of iron pipe 
 with a bore of a quarter of an inch or so, quite open at 
 the end through which the oil is free to trickle. It is 
 humanly impossible for such a thing to become choked. 
 
 As it drips from the end of this tube the oil falls 
 upon what might best be described, perhaps, as a 
 kind of flat shovel. 
 
 Probably every reader has noticed the shovel with 
 which the cashier at the bank handles large quantities 
 of coins. 
 
 Let the tube just described take the place of the 
 handle of such a shovel ; then turn up the front edge a 
 little and cut a number of notches in the ridge so 
 formed. You now have a fairly good idea of the burner. 
 
 Oil from the tube flows on to the flat bottom of the 
 shovel, distributes itself fairly thereon and then 
 proceeds to drip out through the notches. Thus 
 there falls from the front edge of the shovel a little 
 curtain of dripping oil. The shovel is 4 ins. wide, and 
 so the curtain is 4 ins. wide, too. The notched edge over 
 which the oil falls is appropriately termed the "weir." 
 
 Now just underneath the shovel is a very fine 
 slit, also 4 ins. long, through which steam blows 
 in horizontally, so that the vertical curtain of oil 
 drops, as it were, upon a horizontal ribbon of steam. 
 
 91 
 
OIL-DRIVEN LOCOMOTIVES 
 
 It is hardly necessary to point out how the steam 
 will carry the oil forward, at the same time breaking 
 it up into fine spray. Thus the combined jet of steam 
 and oil enters the fire-box of the engine. There it 
 encounters a certain amount of air and bursts into 
 flame. 
 
 No fuel is used, in this system, except the oil. 
 The fire-bars are entirely removed, the ash pan, 
 which usually occupies a place just under the bars 
 and catches the ashes which fall between them, 
 disappears too. Instead, the fire-box is fitted with 
 a special floor of iron on which is placed a layer of 
 fire-brick. Several fire-brick arches, too, are built 
 in the fire-box for a purpose which will be apparent 
 in a moment. 
 
 In the earlier oil-burning systems the burner or 
 jet was introduced from the rear of the fire-box 
 near the door through which the fireman usually 
 throws in the coal. With this system, however, a 
 totally different plan is adopted. The burner is in 
 the front of the fire-box underneath the boiler. The 
 jet enters underneath a small brick arch where it 
 bursts into flame. But for the arch the heat would 
 be drawn straight up and through the tubes, but 
 it is more economical to make it play first round 
 the fire-box, so the arch is introduced. Consequently 
 the flame is projected towards the rear of the fire- 
 box, at which point more air is met, which air, having 
 entered through channels in the brick floor, is already 
 heated by heat which would otherwise have been 
 lost. The flames then encounter another arch which 
 throws them backward and upward, where yet 
 
 92 
 
OIL-DRIVEN LOCOMOTIVES 
 
 another arch is met with, and the result is a swirling 
 action on the part of the flames which ensures perfect 
 combustion and an economical distribution of the 
 heat before the hot gases finally pass through the 
 tubes and up the chimney. 
 
 The fire is lit in a most simple manner. A handful 
 of oily cotton waste is lit and thrown into the fire- 
 box ; then the steam and oil are turned on and 
 instantly there is a hot fire. One difficulty presents 
 itself at this point, namely, that when the engine is 
 cold there is no steam to be got from it. Hence at 
 starting a temporary supply has to be brought by 
 means of a flexible pipe from some other source. 
 That can easily be arranged for, however, at every 
 engine shed. 
 
 The supply of oil and the supply of steam can both 
 be controlled by means of simple valves in the cab 
 of the engine, so that the flame is at all times under 
 perfect control from the cab. 
 
 Should this book fall into the hands of anyone 
 who was in Mesopotamia he will probably remember 
 the most objectionable little insect met with out 
 there which rejoices in the name of " Scarab." The 
 " scarab " seems to be an exceedingly well-designed 
 and efficient little beast, which is exceedingly diffi- 
 cult to kill. His construction is such that he is 
 apparently in working order at all times and under 
 the most adverse conditions. Hence Colonel Mac- 
 donald conceived the happy idea of calling his oil- 
 burner the " scarab," indicating that it possesses 
 those excellent qualities of strength and reliability 
 so necessary in connection with a locomotive. 
 
 93 
 
CHAPTER VII 
 BRAKES : HOW THEY WORK 
 
 THE story of the railways is largely one of 
 safeguards. The lessons of experience have 
 been applied regardless of cost in order to 
 make railways safe for those who travel by them. 
 
 And one of the most important of these is the 
 " continuous brake." Why " continuous " ? you 
 may ask. Think a moment. 
 
 A train is rushing along at fifty or sixty miles an 
 hour, and for some reason or other is suddenly called 
 upon to stop. Suppose that under such conditions 
 only the engine had a brake. The speed of the 
 locomotive would by the application of this be 
 suddenly checked, but the vehicles behind, because 
 of their great momentum, would come pressing on. 
 At the best, they would push the engine and so 
 prevent it from stopping in so short a space as it 
 could easily do if it were by itself. At the w r orst, the 
 hinder ones, by pushing the front ones against the 
 engine, might actually force them off the line long 
 before the speed had been materially reduced, 
 resulting in a serious accident. In between these 
 two extremes there are a vast range of possibilities, 
 all of them more or less unpleasant for the traveller. 
 
 The result is that all fast-moving trains are now 
 
 94 
 
BRAKES : HOW THEY WORK 
 
 fitted with some form of continuous brake, by means 
 of which the driver, or in an emergency the guard, 
 or even a piece of automatic signalling apparatus, 
 can apply the brake quickly to every vehicle in the 
 train. 
 
 Another advantage of the continuous brake is 
 this. It can be easily, and, in fact, always is, so 
 arranged that it applies itself automatically in the 
 event of certain things happening. For instance, 
 one of the dangers of railway working is that a 
 
 normal direction 
 of traffic 
 
 Fig. 4. DIAGRAM SHOWING HOW CATCH -POINTS ABE MADE, 
 
 IN ORDER TO CATCH RUNAWAY WAGONS. 
 
 A train passing from A to B will set the points for itself, 
 but should anything break away and run back from B to- 
 wards A the catch-points will throw it off the line, thereby 
 preventing it injuring anything else. 
 
 coupling may break and a portion of a train be left 
 behind. Now should that occur in ascending an 
 incline, the hind portion of the train would almost 
 certainly run back of its own accord, probably 
 dashing into something before it had gone far. A 
 runaway train of that sort ignores signals, and the 
 only thing that can be done with it is to turn it into 
 a siding where it can expend its stored- up energy 
 in demolishing a buffer-stop or something of that 
 ^sort. In many cases there are placed at the foot 
 of inclines what are called " catch points " for this 
 
 95 
 
BRAKES : HOW THEY WORK 
 
 very purpose. They are like ordinary points, except 
 that they are not controlled by rods, but by springs. 
 A train passing through " catch points " in the 
 normal direction, simply pushes them into the right 
 position for itself as it passes over, but as soon as 
 it has passed the springs re-set them so that if the 
 train were to run back it would be turned into a 
 siding or short length of line. In either case, if it 
 came with any speed, it would be wrecked, but the 
 catch points would at all events save other trains 
 from being wrecked by it. 
 
 Catch points and similar devices are employed to 
 catch and turn aside runaway goods wagons, but 
 passenger vehicles are dealt with by the automatic 
 brake. 
 
 It stands to reason that in order to control the 
 brakes on every vehicle there must be something or 
 other which runs the whole length of the train, and 
 it is arranged that the severance of that something 
 should put the brake on. 
 
 The " something " is, in fact, a pipe, known as 
 the " train pipe," and the motive power by which 
 the brakes are worked is in some cases compressed 
 air and in others the precise opposite, a " vacuum." 
 Some railways prefer one system, some the other, 
 while many of them have stock fitted with both so 
 that they can work over lines where either system 
 prevails. 
 
 Let us take first the automatic vacuum brake. 
 Under each vehicle there is a cylinder with a piston 
 in it and a piston rod projecting through the cover 
 by which the motion of the piston is communicated 
 
 96 
 
CAB INDICATOR. 
 
 This represents one part of an apparatus for indicating in the cab of a locomotive 
 the state of the signals which it passes. This part is fixed to the engine ; near the 
 signal is an inclined plane with which this comes into contact as it moves over. 
 
 There are several types of this apparatus, this particular one being the invention of 
 Messrs. Sykes, of Clapham, London. 
 
BRAKES : HOW THEY WORK 
 
 to the outside. The position of the cylinder is 
 vertical with the piston rod projecting downwards. 
 
 These cylinders are not very high because of the 
 limited space in which they have to be fixed, under- 
 
 to tram 
 pipe. 
 
 Fig. 5. DIAGRAM SHOWING HOW THE VACUUM BRAKE WORKS. 
 (N.B. For the sake of simplicity the piston-rod is not shown.) 
 
 (1) When the air is sucked out the ball lifts, and the air is 
 drawn from above the piston as well as from below. 
 
 (2) When air is admitted the ball prevents it reaching the 
 upper side of the piston ; therefore the piston is forced upwards. 
 
 neath the vehicle, but they are of large diameter, the 
 largest being as much as 21 ins. 
 
 Connected with the cylinder there is a vacuum 
 
 reservoir. In some cases this is formed by a steel 
 
 envelope which surrounds the cylinder itself. In 
 
 other cases it is a separate vessel joined to the cylinder 
 
 G 97 
 
BRAKES : HOW THEY WORK 
 
 by means of a pipe. In either case it is always in 
 communication with the upper part of the cylinder, 
 above the piston. 
 
 Either embodied in the piston itself or else in the 
 piston rod there is a valve of the kind known as 
 " non-return," meaning that air can pass freely 
 through it in one direction, but cannot return. It 
 consists generally of a metal ball held in a little 
 chamber, in the floor of which is a hole. The area 
 just round the hole forms what is termed the " seat- 
 ing " for the ball, and the action is that air coming 
 up through the hole raises the ball easily and passes 
 by it, while should it attempt to return the ball 
 covers the hole and the harder the air presses back 
 the more firmly is the ball held down upon the 
 seating. 
 
 The under part of the cylinder, below the piston, 
 is in communication with the train pipe, one end of 
 which, of course, terminates upon the engine. 
 
 We can now see how the whole apparatus works. 
 The driver, by means of an " ejector," which will 
 be described later, is able to withdraw air from the 
 train pipe, thereby causing the air to be sucked also 
 from the cylinders. The ball valves, under these 
 conditions, are open, allowing the air to be drawn 
 out freely, with the result that the whole apparatus 
 is exhausted of air. Pipes, cylinders, vacuum 
 reservoirs, all are freed from air, and in those cir- 
 cumstances the piston falls down to the bottom of 
 the cylinder and the brake is " off." 
 
 Now suppose that the driver lets air into the train 
 pipe. It rushes along, flooding the lower part of 
 
 98 
 
BRAKES : HOW THEY WORK 
 
 cylinder after cylinder ; the ball valves coming into 
 operation prevent the air from passing the pistons, 
 and the whole pressure of the atmosphere, about 
 15 Ibs. on every square inch, acting upon each piston 
 forces it upwards, draws up the piston rod and 
 operates the system of rods and levers by which the 
 brake blocks are applied to the wheels. 
 
 Release pipe 
 
 fig. 6. DIAGRAM SHOWING HOW THE VACUUM BRAKE 
 
 WORKS ON AN ELECTRIC VEHICLE. 
 
 The air pump, acting through the release pipe, always keeps 
 up a good vacuum in the release reservoir. When the driver 
 wants to release the brake he opens the release valve (by 
 electricity), and the brake is released almost instantly. 
 
 It may seem strange, but this action requires quite 
 an appreciable time to take effect along a long train. 
 It might be as long as half a minute after the 
 driver had opened his valve before the brakes went 
 on on the last vehicle, so some special provision has 
 to be made to speed things up. This is called the 
 accelerator valve. One is fixed in the train pipe 
 near each cylinder and its action is this. As soon 
 as air begins to reach the accelerator, and the vacuum 
 begins to fall, this valve opens and lets air freely 
 into the pipe, thereby hastening the action not only 
 
 99 
 
BRAKES : HOW THEY WORK 
 
 of the cylinder adjacent, but also the accelerator and 
 cylinder of the next vehicle. In effect, the result is 
 that instead of all the air required to apply the brakes 
 having to travel right along from the engine, through 
 many feet of pipe, entrances are formed for the 
 air on each vehicle. As soon as they have done 
 their work the accelerator valves close automatically 
 and remain closed until they are required again. 
 
 The train pipe consists of metal tubing upon the 
 vehicles, with flexible ends, each end being fitted 
 with a cleverly designed union by which it can be 
 quickly and securely attached to the flexible pipe 
 of the next vehicle. Most travellers have at some 
 time or other watched the operation of coupling 
 and uncoupling these flexible pipes. 
 
 Now supposing a coupling were to break and a 
 part of a train thereby became detached from the 
 part in front of it, the flexible pipe would of necessity 
 be torn in two also. Its open ends would then 
 admit air and the brake would be applied with the 
 maximum of force to both portions. The driver 
 would know that something had happened and the 
 rear portion, no matter if it were on a steep incline, 
 could not run away backwards. 
 
 Reference has been made elsewhere to the injector, 
 by means of which a jet of steam throws water into 
 the boiler. The " ejector," by which the air is drawn 
 out of the train pipe and the vacuum created, is the 
 same thing working the opposite way. Instead of 
 throwing something in, it throws something out ; 
 its very name signifies that. It consists of an arrange- 
 ment of nozzles through one of which steam blows 
 
 100 
 
BRAKES: HOW THEY WOUK 
 
 in such a way that it carries the air along with it. 
 This has to be kept going almost continuously, in 
 order to maintain the vacuum in spite of the numerous 
 little leaks which it is impossible to prevent. 
 
 It will be noticed that only the engine can release 
 the brake off a vehicle fitted with the vacuum brake, 
 and the point will at once suggest itself that very 
 awkward conditions would arise if an odd coach 
 needed to be moved a short distance by man power 
 or by a horse. The brakes would be on and there 
 might be no engine at hand to release them. 
 
 This is provided against by very simple means. 
 Underneath a coach fitted for the vacuum brake, 
 usually about the middle of its length, there will be 
 noticed a loose wire. There is sometimes an arrow 
 painted upon the frame of the coach to call attention 
 to the position of it. 
 
 It is only necessary to pull this wire in order to 
 release the brake. What it does is to operate a little 
 valve which lets air into the cylinder above the 
 piston, destroying the vacuum entirely and leaving 
 the brake free. When the vehicle is coupled up 
 once more and the air exhausted by the engine the 
 brake acts just the same as before. 
 
 What has been said so far applies to the use of 
 the vacuum brake on steam trains ; when applied 
 to electric trains certain modifications are necessary. 
 
 In the first place an exhauster or air-pump driven 
 by an electric motor has to take the place of the 
 ejector. Then, again, special provision has to be 
 made for the rapid release of the brakes. An essential 
 feature of the electric propulsion of trains is the 
 
 101 
 
BRAKES: HOW THEY WORK 
 
 quickness with which they can re-start. Anyone 
 who has watched the rapid succession of trains 
 pouring through a station on one of the London 
 Underground lines, for example, at a busy time of 
 the day, will realize what this means. Yet to create 
 a vacuum, from the very nature of things, takes 
 time, so that the same arrangement which supplies 
 perfectly the needs of a steam train might be too 
 slow in its action for an electric train. 
 
 To meet this difficulty there is a second pipe 
 running the whole length of the train called the 
 release pipe, and connected to it at various points 
 are large vessels which form vacuum reservoirs, and 
 which are called " releasing reservoirs." 
 
 At intervals the release pipe is connected to the 
 train pipe by means of connecting pipes, in each of 
 which there is inserted a valve called a " release 
 valve." Now this valve is operated by electricity, and 
 the purpose of it is to hasten the release of the brakes. 
 
 The brakes are applied in the ordinary way, by 
 the opening of a valve in the driver's cabin. To 
 release them the driver closes this valve again, and 
 the exhauster, which runs continuously, then begins 
 to restore the vacuum. At the same time an electric 
 current opens the release valves, putting the train 
 pipe at several points into communication with the 
 release pipe and its release reservoirs. The reservoirs 
 therefore help the exhauster and the result is a 
 quick release of the brakes. The highest vacuum 
 which is practically possible is maintained in the 
 release pipe and reservoirs to ensure the utmost 
 efficiency frornjthis arrangement. 
 
 102 
 
BRAKES : HOW THEY WORK 
 
 We can now turn to the alternative system, where 
 the brakes are worked by compressed air. 
 
 This device is called the Westinghouse brake, 
 after that versatile American engineer, George 
 Westinghouse, who invented it about fifty years ago. 
 
 To commence at the beginning, there is on the 
 engine a small subsidiary engine combined with an 
 
 >IVI BY OPENING 
 YTHICH CUAD CAN 
 APPLY ERAKI 
 
 loxa 
 
 C^ CYUNDER ^ 
 
 run FOR mGAftINO BRA.KB 
 WKCM NOT CONNECTED 
 TOJfflNI 
 
 TRIPLE VAJLVJ 
 
 ^PRESSURE GAUGE 
 TO SHOW GUARD 
 THAT APPARATUS 
 IS WORKING 
 
 COCK : 
 
 TKAqi PIPE 
 
 Fig. 7. DIAGRAM SHOWING HOW THE WESTINGHOUSE BRAKE 
 
 IS ARRANGED ON A GUARD'S VAN. 
 
 Pressure in train pipe so operates the triple valve that air 
 escapes from cylinder, but reservoir is filled. Fall of pressure 
 in train pipe sends compressed air from reservoir into cylinder 
 and applies the brake. 
 
 air-pump for the purpose of maintaining a supply 
 of compressed air. This little engine is familiar to 
 many because it advertises its presence by working, 
 very often, when the locomotive is standing in a 
 station. It is of a type which is very usual where 
 pumping is the work required ; it has no rotating 
 parts, but has simply two cylinders, one above the 
 other, a single piston rod connecting the piston 
 in one cylinder to the piston in the other. 
 
 The upper cylinder is the steam cylinder, and 
 
 103 
 
BRAKES : HOW THEY WORK 
 
 its piston being forced up and down by the steam 
 moves the piston in the air cylinder below, thereby 
 pumping the air. 
 
 A very usual place for this little engine or com- 
 pressor is on the side of the locomotive just forward 
 of the driver's cab. 
 
 The air which it pumps passes into the main 
 reservoir beneath the engine, while the steam which 
 drives it passes through a valve controlled by the 
 pressure of the air, so that the compressor works 
 automatically. It pumps air into the reservoir 
 until the pressure reaches 90 Ibs. per square inch 
 and then it stops. When the pressure falls appreciably 
 it starts again and raises it once more to 90 Ibs. 
 
 The valve which does this is beautifully simple, 
 being little more than a small cylinder with a piston 
 in it which is normally held up by a spring. This 
 cylinder is in communication with the reservoir, 
 and the strength of the spring is so adjusted that at 
 90 Ibs. the pressure of the air just overcomes the 
 spring, moves the piston and thereby closes the 
 passage for the steam. 
 
 When the pressure falls, the spring raises the 
 piston again, opens the passage for the steam and 
 sets the compressor going. 
 
 Thus far, then, we have a " main reservoir " upon 
 the engine, charged with air to a pressure of 90 Ibs. 
 per square inch. There is a passage from this reser- 
 voir to the " train pipe," but the pressure there is 
 only about 70 Ibs., so a further valve is introduced 
 between the main reservoir and the train pipe which, 
 acting on the same principle as that just described, 
 
 104 
 
Ry permission of th 
 
 \McKenzie, Holland & Westinghouse Signal Co. 
 AUTOMATIC TRAIN STOP. 
 
 When the signal is at danger the little arm in the centre of the picture stand? 
 up so that it a train were to pass it it would strike the little hanging lever upon the 
 train. This would put on the brake and stop the train. As soon as the signal goes 
 to " safety " the arm falls down so that a passing train is not affected. 
 
BRAKES : HOW THEY WORK 
 
 allows the air to pass into the train pipe until the 
 pressure there is 70 Ibs. The effect of this is to make 
 quite sure that the train pipe shall always, except 
 when it is desired otherwise, be fully charged with 
 air at 70 Ibs. 
 
 The air flows through the train pipe right along 
 the train, thereby finding its way into the " auxiliary 
 reservoirs," of which there is one on every vehicle, 
 generally, including the engine itself. The purpose 
 of the auxiliary reservoir is to maintain a store of 
 compressed air ready to apply the brake at any 
 moment. Note here the precautions against the 
 possibility of failure. The compressor, being con- 
 trolled automatically, keeps the main reservoir full 
 at 90 Ibs. The " feed valve " again acting auto- 
 matically, ensures that the train pipe shall be fed 
 from the main reservoir until it is filled to the pressure 
 of 70 Ibs., and from here the air passes to the auxiliary 
 reservoirs, so that close to each spot where the 
 brakes may need to be applied there is a store of 
 compressed air, ready to do the work. 
 
 On each vehicle there is a cylinder with a piston 
 in it and piston rod projecting through one end. 
 The normal position of the piston is at one end of 
 the cylinder, this being ensured by the action of a 
 spring inside the cylinder which pushes the piston 
 to that end. The admission of compressed air over- 
 comes the force of the spring and moves the piston 
 to the other end, thereby moving the rods and levers 
 which apply the brakes. 
 
 At first sight it would seem to be the simplest and 
 best thing just to put the cylinders into communi- 
 
 105 
 
BRAKES : HOW THEY WORK 
 
 cation with the train pipe and to force air in when it 
 was desired to put the brake on. That, however, 
 would not be automatic. The severance of the train 
 pipe would leave the brake " off." A leak in the train 
 pipe or in any part of the apparatus would have the 
 same result, so that the first principle of railway 
 apparatus, namely, that failure shall make for safety, 
 would be violated. The action is, therefore, reversed 
 by a very wonderful little valve called a " triple 
 valve," which is really the essential part of the whole 
 apparatus. 
 
 In this ingenious but simple contrivance we have, 
 once more, a little cylinder with a piston in it, the 
 movement of which actuates a small slide valve in 
 principle like the slide valve of the locomotive itself. 
 
 The cylinder of the triple valve is in communica- 
 tion with the train pipe, and so long as the pressure in 
 the pipe is up to the normal 70 Ibs. the piston is 
 held over in its extreme position, under which con- 
 ditions a " port " is open which allows the air to 
 pass into the auxiliary reservoir, thereby keeping 
 the reservoir charged. 
 
 But suppose something happens to cause the 
 pressure in the pipe to fall ; the piston then moves, 
 closing the connection between pipe and reservoir, 
 but putting the reservoir into communication with 
 the cylinder. Compressed air from the reservoir 
 then rushes into the cylinder and applies the brake. 
 
 Thus we arrive at the curious fact that although 
 the brake is applied by the pressure of air, it is really 
 actuated by a fall in pressure. The pressure is 
 stored up in the reservoir, and the fall in the train 
 
 106 
 
BRAKES : HOW THEY WORK 
 
 pipe liberates it and guides it into the cylinder, there 
 to do its work. 
 
 When the pressure in the train pipe is restored the 
 triple valve goes back to its normal position, putting 
 the train pipe into communication with the reservoir 
 and at the same time letting out the air from the 
 cylinder, so that the spring is able to assert itself 
 once more and release the brake. 
 
 The driver has, in his cab, a gauge which tells 
 him the pressure in the main reservoir and also in 
 the train pipe. He also has a valve by which he can 
 at any moment lower the pressure in the train pipe 
 and so put on the brakes. The guard has a valve 
 too, by which he can do the same thing, while the 
 breakage of a coupling will do it automatically. 
 
 On electric trains the compressor is, of course, 
 worked by an electric motor instead of by steam. 
 
 107 
 
CHAPTER VIII 
 
 THE CONSTRUCTION OF A BRITISH 
 RAILWAY 
 
 WHEN we take a trip on a railway we seldom 
 think much about how the line came to 
 be built. It has probably been where it 
 is as long as we can remember, and we forget that it 
 ever had to be thought out and put there. 
 
 Could we go far enough back we should probably 
 find that every railway originated in the mind of 
 some particular man, probably some humble in- 
 dividual who will be for ever unknown. 
 
 It comes about in this way. The people of some 
 town feel the need for a better means of communi- 
 cation with some other town ; a rising port, perhaps, 
 needs to attract more trade ; a new colliery or large 
 factory has goods which it wants to distribute more 
 expeditiously ; or a landowner has some land which, 
 with better communication, would become more 
 valuable for residences or factory sites. These are 
 a few of the impulses which may set someone's 
 mind in the direction of promoting a railway. 
 
 The man who first conceives the idea talks about 
 it to others, and they spread the story until enough 
 men have been gathered together with sufficient 
 
 108 
 
CONSTRUCTING A BRITISH RAILWAY 
 
 financial backing to make the thing fairly sure of 
 success. 
 
 There are generally men with money to invest, or 
 who can influence others who have it, ready to interest 
 themselves in any scheme which offers a reasonable 
 prospect of becoming a paying concern. Thus it is 
 not as difficult to set going a project for building a 
 railway as might at first sight seem to be the case. 
 
 The first essential is a good scheme ; a scheme, 
 that is, which will fill a want or create a want on the 
 part of the public. It is no good putting down a 
 railway if no one is ever wishful to travel upon it or 
 to send goods by it. On the other hand, if a man 
 hits upon the fact, hitherto overlooked, that a line 
 from X to Y would attract a lot of traffic, he has a 
 very good chance of interesting others who will 
 gladly assist in making the line. 
 
 The promoters, after a general investigation of the 
 matter, usually employ some eminent firm of engineers 
 to investigate it thoroughly. These people, not 
 satisfied with the information to be culled from the 
 Ordnance Maps, make a careful survey of the route, 
 probably of several alternative routes. One of these 
 perhaps will be the shortest, but will necessitate 
 several costly tunnels, cuttings, viaducts or bridges. 
 Another, possibly, will be longer but with fewer of 
 these difficulties. One may pass certain villages 
 where a little traffic may be picked up ; another 
 may go through other villages. All these facts, and 
 many others, have to be weighed up and balanced 
 against each other in order to decide ultimately 
 which route will be the best of all. 
 
 109 
 
CONSTRUCTING A BRITISH RAILWAY 
 
 As an example of the kind of fact which may have 
 a powerful bearing on the choice of route and yet 
 may be quite unnoticed by the casual observer, we 
 may take the balancing of the two kinds of earthwork. 
 A valley, for instance, may call for the construction 
 of a long embankment ; the question then arises, 
 where is the earth to come from ? If the amount of 
 earth needed for the embankment is about equal 
 to the earth which will be dug out of a cutting on 
 another part of the line, then the difficulty vanishes. 
 So in considering the practicability of a certain 
 route, it is necessary to see if cuttings and embank- 
 ments can be made to balance each other. After the 
 line is made, someone comes along who has not 
 carefully gone into the matter and indignantly asks, 
 " Why ever did they not take such and such a route, 
 it would have been easy to make an embankment 
 across so and so," and probably that was the very 
 thing which the promoters wanted to do, but the 
 materials for making that embankment were not 
 available. 
 
 Let us suppose, however, that all these matters 
 have been thoroughly thrashed out and the plans 
 completed. The next thing is to get authority from 
 Parliament. 
 
 WhyTshould that be necessary ? is a question which 
 may be asked. A man can build a house if he wants 
 to do so, why should he not be able to build a railway 
 without the authority of Parliament ? 
 
 The reason is that the house builder can buy his 
 land by mutual arrangement with the owner, whereas 
 the railway promoters may come across a case where 
 
 no 
 
CONSTRUCTING A BRITISH RAILWAY 
 
 they need a piece of land the owner of which does 
 not wish to part with it. 
 
 Thus one man could hold up a large scheme by 
 refusing to sell a small plot of ground, and, to prevent 
 that, Parliament has to step in and give the pro- 
 moters of the railway the power in such a case to 
 take the land which they need, giving the owner 
 compensation, of course. 
 
 In the old days this led to many amusing incidents. 
 Before Parliamentary powers can be obtained surveys 
 have to be made, for until the surveys have been 
 made the Bill for presentation to Parliament cannot 
 be prepared. Consequently it is necessary for the 
 surveyors to go on to private land to make their 
 surveys before they have the legal right to do so. 
 Just imagine, then, an irate old farmer who does not 
 want his land interfered with, finding a couple of 
 men calmly surveying it in order to prepare a Bill, 
 the object of which is to take it from him. There 
 have been cases where, under such conditions, a 
 ferocious bull has found its way into the field or a 
 particularly large dog, to say nothing of farm hands 
 armed with scythes and other warlike implements. 
 It does not happen often, to-day, because the modern 
 farmer realizes that a new railway will probably 
 benefit him and, at all events, he will be adequately 
 compensated, but in the old days that was not the 
 case, and the men who made the preliminary surveys 
 often had exciting times. 
 
 All that is got over in time and the Bill prepared. 
 Like all Bills it commences with a " preamble " 
 which sets forth the reason why it is put forward. 
 
 in 
 
CONSTRUCTING A BRITISH RAILWAY 
 
 In this case it must show that the proposed railway 
 is required for the public good. Parliament does 
 not, it must be well understood, give powers to 
 promoters because of any affection for them, but 
 only because the scheme they are proposing to 
 carry through is for the benefit of the public. 
 
 So the first thing that Parliament considers is 
 whether or not the public actually need the line, 
 and whether they are, therefore, justified in making 
 certain individuals do what they may not want to 
 do, for the good of the community generally. 
 
 Bills such as these are usually considered by a 
 joint committee of both the Houses of Parliament, 
 and those who are promoting it, as well as those who 
 are against it (for any interested person can oppose, 
 if he wishes to) can be represented by barristers 
 who can argue the case for them. 
 
 If the committee consider that the public need is 
 not sufficiently great to justify them in going on 
 with the Bill they decide that the " preamble is not 
 proved," and there the matter ends. If, however, 
 they find that it is proved, then they go further 
 into the matter, clause by clause, until every detail 
 has been thoroughly thrashed out and settled. 
 
 After all the formalities have been gone through 
 and probably a great many changes made in order 
 to reconcile many interests, the Bill is passed and 
 becomes an Act of Parliament. Many of the curious 
 and unaccountable things which railways do, by 
 the way, is the result of compromises which are 
 made as the Bill goes through Parliament, in order 
 to harmonize conflicting interests. 
 
 112 
 
T 
 
 2 1 . 
 
 ? * s 
 
 o g> 
 
 u S 
 
 aj u 
 
 ^ -s s 
 
 S5 & a 
 
CONSTRUCTING A BRITISH RAILWAY^ 
 
 The next step is to make a contract with someone 
 for the construction of the line. A vast number of 
 drawings are first produced by the engineers, giving 
 all manner of details. In fact, the line is first con- 
 structed in the minds of the draughtsmen in the 
 engineer's office, to an extent which would surprise 
 many non-technical people. The smallest details 
 are carefully thought out and put down on paper. 
 
 From these drawings a schedule of quantities is 
 prepared, by which is meant lists of the materials 
 to be supplied and work to be done. These lists, 
 too, are wonderfully complete, considering that so 
 far the thing only exists in imagination. 
 
 Copies of the schedules are sent out to the people 
 who are invited to tender for the work, while the 
 drawings are placed in some convenient room, so 
 that those who are going to tender can come and 
 study them. 
 
 Then each tenderer puts down his prices against 
 the items in the lists (there are possibly thousands 
 of items) works them all out, adds them up, makes 
 allowances for any special risks or liabilities which 
 occur to him and finally arrives at a total. This he 
 fills in upon the tender form prepared for the purpose 
 and sends it in. 
 
 On a certain day the directors of the railway 
 company (for such the promoters have now become) 
 sit in state for the purpose of receiving these tenders. 
 They all come in sealed envelopes and are opened 
 at the meeting. A list of them is usually made, 
 after which they are referred to the engineer and other 
 officials for them to go through and report upon. 
 H 113 
 
CONSTRUCTING A BRITISH RAILWAY 
 
 At a subsequent meeting one is accepted, not always 
 the lowest, but the one that the directors consider 
 most beneficial after taking everything into account. 
 
 Meanwhile, of course, negotiations have been going 
 on for the purchase of the necessary land. In most 
 cases the company's land agents will be able to 
 arrange amicably with the owners, but in a few, 
 possibly, the price will have to be settled by arbitra- 
 tion. 
 
 As soon as it can be arranged the land passes, 
 piece by piece, if necessary, into the hands of the 
 contractors, who then commence active operations. 
 
 The work is attacked at many convenient points, 
 a bridge here, a tunnel there, a cutting somew r here 
 else, the trains with spoil from the cuttings running 
 to the places where embankments are required. 
 Where an embankment has to be interrupted to 
 allow a road to pass, and the line, as so often is the 
 case, has to be carried upon a brick arch, the brick- 
 work is done first, the bricks being carted by road, 
 so that the arch stands for a time isolated amid the 
 surrounding country, often looking very strange, 
 like a monumental arch that has lost its way. Gradu- 
 ally, however, the earthen embankment is creeping 
 along. The little tipping trucks with earth come 
 along temporary lines laid on that part of the bank 
 which is finished, and each tips up at the end of its 
 run, dropping its contents down the steep side of, 
 or rather end of, the growing heap. Thus the earth- 
 work goes on until it reaches the isolated arch and 
 permits the line to be carried on over it. 
 
 Where wider and more important roads call for 
 
 114 
 
CONSTRUCTING A BRITISH RAILWAY 
 
 a steel bridge, the brick or stone abutments which 
 support its ends are built up and the embankment 
 brought up to them, the steel girders being either 
 hoisted up from the road below or else carried by 
 rail on the line above at a later stage. 
 
 Tunnelling is a problem which has to be faced in 
 the construction of most lines, but that will be dealt 
 with fully in another chapter. 
 
 Where large excavations have to be made, such 
 as deep cuttings, mechanical aids are employed in 
 addition to the pick and shovel of the navvy. These 
 machines are called steam navvies, or sometimes 
 mechanical shovels. 
 
 Speaking of names, it is rather interesting to trace 
 the origin of the word navvy. It dates back a 
 hundred years or so to the time when canals were 
 being constructed all about the country, just before 
 the era of railways. Attracted by the better wages 
 to be earned, many men who till then had been 
 agricultural labourers drifted away from the country- 
 side to the canal works, where they were employed 
 mainly in digging out the earth to form the water- 
 ways. Passing from place to place, wherever the 
 work might be going on at the moment, they ac- 
 quired considerable skill in their work, so that 
 eventually they became a semi-skilled class, and 
 whenever a new canal was started the contractors 
 naturally looked about to find as many men as 
 possible of this class, for it is quite a mistake to 
 think that any able-bodied man can do navvy's 
 work, without experience. 
 
 It is probable that the outdoor nature of the life 
 
CONSTRUCTING A BRITISH RAILWAY 
 
 attracted many men, and the frequent moving from 
 one job to another satisfied the roving instinct which 
 afflicts a good many Britishers. 
 
 Anyway, this class came into existence and the 
 work upon which they specialized, which had, 
 indeed, called them as a class into existence, was the 
 construction of " navigation canals," whence they 
 came to be termed navigators, which in time was 
 corrupted into " navvies." 
 
 But to return to the steam navvy. This is a 
 powerful machine mounted upon wheels so that it 
 can be moved upon rails which are laid down specially 
 for it. It contains a steam engine, complete with its 
 boiler, also a long, powerful arm which it can raise 
 and lower at will. At the extremity of the arm is 
 what might be called a gigantic hand with its palm 
 upwards, the finger nails, to complete the simile, 
 being pointed and strong. 
 
 Let us picture it at work on the side of a hill into 
 which it is digging its way in order to cut out one of 
 those huge furrows which we call a railway cutting. 
 
 It stands upon a small piece of level ground which 
 has been prepared as its starting-point, and from 
 that it advances towards the side of the hill. Then 
 it lowers its arm to the ground level, immediately 
 raising it again in a powerful sweep, scooping away, 
 as it does so, a huge handful of earth from the hill- 
 side. The lifted earth is then dropped out through 
 a trap door which forms the palm of the " hand " 
 into a waiting truck, and the hand descends once 
 more to pick up another handful. 
 
 One of these machines can pick up as much as 
 116 
 
CONSTRUCTING A BRITISH RAILWAY 
 
 half a ton of earth at one movement, so it is easy to 
 see that under favourable conditions it can displace 
 quite a large number of its human namesakes. 
 
 Speaking generally, however, there is not a great 
 amount of machinery used in the construction of a 
 railway. There are lots of trucks and wagons of 
 various sorts and small locomotives to haul them 
 about, also a few cranes mounted upon railway 
 wheels so that they can be moved about for lifting 
 heavy stones and the like, also, in special places 
 steam navvies, but on the whole the construction of 
 a railway is largely the work of the human machine. 
 The reason for this is that the work is so varied 
 and spread out over so large an area that nothing 
 can compare with that most mobile and adaptable 
 of all machines, the human body. 
 
 When all the earthwork has been done the line is 
 by no means finished. The temporary tracks laid 
 down by the contractors for their own convenience 
 are not suited for the regular traffic. For one thing, 
 they rest merely upon earth, which under the pressure 
 of the ordinary loads of a railway would give way. 
 The small, light engines and the little trucks of the 
 contractor can safely pass over tracks which would 
 be hopelessly weak for heavy goods and passenger 
 engines with their trains. 
 
 The level to which the earthwork, the founda- 
 tions of the line, are raised is called " formation level." 
 Upon the top of that comes the ballast to a depth of 
 about 18 ins. 
 
 This consists of stones of varying sizes. Such 
 stuff as shingle from the seashore is used in some 
 
 117 
 
CONSTRUCTING A BRITISH RAILWAY 
 
 places, but better still is stone from a quarry, because 
 the rough surfaces and sharp corners of the latter 
 cause it to bind together better into a mass which 
 is solid and strong, yet has interstices through which 
 water can make its way downwards. 
 
 The purpose of the ballast is to distribute the 
 weight so that each sleeper really may rest upon an 
 area of earth much larger than its own area, also to 
 afford drainage so that the timber sleepers, being 
 kept dry, may last longer, and finally to keep the 
 sleepers in place so that they will not slide sideways. 
 
 Large lumps of stone are placed at the bottom 
 of the ballast, in contact with the earth, the successive 
 layers being made of smaller and smaller material 
 up to the top, where the pieces are quite small. In 
 this top layer the sleepers are buried. 
 
 The chairs, which are made of cast iron, are 
 fastened to the sleepers with iron spikes and in 
 some cases oak pegs. The rails are laid in the chairs 
 and then fastened in by means of blocks of oak 
 driven in tightly. These blocks are termed keys, 
 and so important is their function that the " plate- 
 layers " who look after the line spend quite a con- 
 siderable part of their time watching them, and by 
 judicious blows of a special kind of hammer which 
 they carry keeping them tight. 
 
 It is not generally realized that the chairs are so 
 shaped that the rails are not upright, but cant slightly 
 inwards. This is to make them fit approximately 
 the slope of the wheels. 
 
 The wheels are not cylindrical, but slightly conical, 
 so that they have a natural tendency to keep on 
 
 118 
 
CONSTRUCTING A BRITISH RAILWAY 
 
 the rails apart from the action of the flange or rim 
 which they all have. 
 
 Where a branch or a cross-over occurs, points or 
 switches and crossings are required. At each point 
 one rail called the " stock rail " runs right through, 
 while another rail, the end of which is tapered off 
 to a point, is pivoted near to it, so that it can be 
 made to lie close alongside, or be removed to a distance 
 of about 4 ins. In the first position this " tongue," 
 as it is termed, guides the flange of the wheel to one 
 side or the other, while in the second position it 
 leaves a wide enough gap for the flange to pass 
 through. 
 
 The purpose of a crossing is to form a gap in the 
 rails through which the flange of the wheels can pass 
 as a train crosses over. 
 
 Points and crossings are places where there is a 
 remote possibility of a vehicle being thrown off the 
 line, so they are always protected by " guard rails,'? 
 extra pieces of rail upon which the train does not 
 run, but which, because of their situation, tend to 
 prevent it leaving the other rail. The way in which 
 these guard rails act will be made quite clear by a 
 glance at the diagram on page 123. 
 
 Most branches are on a level, so that one of the 
 branch lines has to cross the opposite main line. 
 This is done by means of crossings just like those 
 used with points. In busy- lines, however, such 
 arrangements are very inconvenient. 
 
 Take as an example the case of a branch which 
 curves off in a " down " direction, and to the right. 
 The " down " branch line then crosses the " up " 
 
 119 
 
CONSTRUCTING A BRITISH RAILWAY 
 
 main line, and the passage of a main line train may 
 have to be held up for a considerable time in order 
 to allow a branch train to cross, or vice versa. There- 
 fore, on busy lines, crossings on the level are often 
 avoided by means of " fly-over " junctions. If the 
 illustration just referred to were of the " fly-over " 
 variety the " up " branch would simply curve round 
 in the ordinary way, for it crosses nothing, but the 
 down branch would first curve to the left and then 
 swing round to the right, passing either under or 
 over the main line. The mutual interference of the 
 two lines is then reduced to the minimum. 
 
 The lines laid by the contractors, as we have seen, 
 are quite temporary, being taken up when they have 
 served their purpose, to give way to lines of a " per- 
 manent " nature. Hence the rails, ballast and all 
 connected with them are spoken of in railway 
 language as the " permanent way." 
 
 When the railway is completed it is divided up 
 into areas, each of which is put under the care of a 
 " permanent way inspector," who, under the general 
 direction of the District Engineer, is responsible for 
 the " permanent way " being kept in perfect order. 
 He has under him a number of gangs of plate- 
 layers, each headed by a " ganger." Each ganger 
 has a " length " of line to look after ; it may be 
 several miles or it may be less, according to the 
 number of lines and amount of traffic. On some 
 railways the lengths are marked off from each 
 other by posts with the names of the respective 
 gangers painted on opposite sides. Every ganger is 
 supposed to walk over his " length " once on Sunday 
 
 120 
 
CONSTRUCTING A BRITISH RAILWAY 
 
 and twice every weekday. His keen, practised eye 
 soon catches sight of anything in the least degree 
 wrong ; if it be within his scope he puts it right, 
 either himself or by his gang ; if not he reports it. 
 
 Thus we see how the line is made and also the 
 scrupulous care which is subsequently exercised to 
 keep it in the most perfect order. It is to this 
 methodical care that we owe in a large degree that 
 almost perfect safety which we enjoy when we travel 
 by train. 
 
 121 
 
CHAPTER IX 
 HOW RAILS ARE MADE 
 
 THE railway is much older than the locomotive. 
 Many years before the birth of Trevithick 
 or Stephenson there were railways along 
 which trucks were drawn by horses. Like most 
 other things these were the result of slow growth 
 or evolution, rather than the sudden invention of 
 one man. 
 
 Starting from the rough path made by a succession 
 of carts passing over the same route came the made- 
 up road where stones or other hard material was 
 placed in order to produce a harder and smoother 
 surface. 
 
 From this it was but a step to lay down timbers 
 for the wheels of the carts to run on. These in turn 
 gave place to cast-iron plates, and it is a curious 
 instance of the survival of words that the men who 
 to-day lay and look after the rails upon the modern 
 railway are not rail -layers, but plate-layers. 
 
 In the early stages the plates had raised edges for 
 the purpose of keeping the wheels from running off. 
 This had the disadvantage that plates so shaped 
 formed gutters in which stones collected, and that 
 led to the next stage in which the plates were quite flat, 
 while a raised edge or flange was put upon the wheels. 
 
 122 
 
HOW RAILS ARE MADE 
 
 The trouble with the cast-iron plates was that as 
 the size of the wagons increased they became more 
 and more liable to break. Hence the introduction 
 of rails of wrought iron, a much tougher material 
 than cast iron. 
 
 Wrought iron has in its turn been displaced by the 
 " mild steel " of the present day. 
 
 ;Fig. 8. A PAIR OF POINTS AND A CROSSING. 
 
 (1) These are the stockrails. They are fixed, like ordinary 
 rails. Notice that every train has one fixed rail to run upon. 
 
 (2) The tongues of the points. It is by moving these that 
 the points are set to guide tha train as required. 
 
 (3) Guard rails. Notice that for a train to leave the rails 
 the flanges of the wheels must jump over the guard rails. 
 
 What, then, is this mild steel, and why is it called 
 " mild " ? 
 
 Like all forms of steel it is an alloy of iron and 
 carbon. Pure iron is almost useless, for the reason 
 that it is too soft. For practical use it needs the 
 hardening effect of carbon. Pig iron, which is the 
 raw material from which all other forms of iron are 
 made, contains at least 2 per cent of carbon. Wrought 
 iron contains a small fraction of one per cent, and 
 between the two come all the different varieties of 
 
 123 
 
HOW RAILS ARE MADE 
 
 steel. Steel which contains less than one-half of 
 one per cent is called " mild " steel, the rest being 
 grouped together as hard steel. 
 
 Iron ore is one of the commonest of substances. 
 It is to be found almost everywhere, but all of it 
 cannot be used, since some of it contains so little iron 
 that to work it would be too costly, while in other 
 cases it is so contaminated with impurities as to be 
 useless. 
 
 It is generally obtained from quarries open to the 
 air rather than from underground mines, and it is 
 broken down by blasting or other quarrying methods, 
 just like stones for road metal. Then it is taken to 
 the iron works to be smelted. 
 
 At the iron works there are huge structures called 
 " blast furnaces," great tall chimney -like affairs 
 built of steel and brickwork and lined with fire- 
 brick. In the bottom of the furnace a fire is made, 
 and this is urged to an intense heat by a " blast " of 
 air which is driven in upon it from nozzles placed 
 all round the zone where the fire is. 
 
 The blast is produced by huge air-pumps driven by 
 a powerful steam or gas engine. 
 
 Roughly speaking, then, we may describe the 
 blast furnace as a huge tube, perhaps 70 ft. long, 
 set up on end, the bottom end being closed and the 
 top open, with the fire lying in the bottom end. 
 There are no fire-bars or grate of any description, 
 the fire simply lying on the solid bottom, the oxygen 
 necessary for its burning being blown in from the 
 nozzles. 
 
 Near the top end is a stage reached by a hoist, 
 
 124 
 
HOW RAILS ARE MADE 
 
 and from this point the ore is tipped so that it falls 
 down and mingles with the fire below. Ore, fuel and 
 limestone are continually being thrown in, in the 
 proper proportions, and the blowing engine is blowing 
 air into the mass every hour of the day and night. 
 
 Now it must be understood that iron ore does not 
 appear at all like iron. It is usually a reddish- 
 looking rock. It is chiefly oxide of iron, but is mixed 
 up with earthy matters of various sorts. An oxide 
 of iron, of course, is a combination of iron and 
 oxygen, and the purpose of the blast furnace is to 
 dissolve that combination and to free the iron from 
 its partner. 
 
 Heat alone will not do this. It will loosen the 
 bonds between iron and oxygen, but it will not 
 separate them. In order to separate them it is 
 necessary to place the ore in the neighbourhood of 
 some other matter for which the oxygen has a greater 
 " affinity " than it has for iron. Fortunately carbon 
 fulfils this condition, and so when heated sufficiently 
 the oxygen leaves the iron and joins the carbon, 
 of which there is a plentiful supply in the fuel. 
 
 It is for this reason that ore and fuel are mixed 
 up together. The fuel serves a double purpose ; it 
 supplies the heat and it also entices the oxygen 
 away from the iron, which latter purpose it could 
 not serve unless it were close to it. 
 
 The liquid iron thus formed collects in the bottom 
 of the furnace, the fire actually floating upon the 
 top of a pond of molten iron. Periodically the 
 furnace is tapped ; a small hole normally plugged 
 with clay is unstopped and out runs the metal. 
 
 125 
 
HOW RAILS ARE MADE 
 
 Periodically, too, a hole higher up is opened and 
 from it is drawn a liquid which is termed " slag." 
 It consists mainly of the earthy impurities out of 
 the ore. The slag, when cool, sets into a hard rock- 
 like substance which is used largely for making 
 roads. 
 
 Before we follow the history of the molten iron 
 to the next stage we should take a final look at the 
 blast furnace. 
 
 In the old days the top was left permanently 
 open and flames belched forth, lighting up the sky 
 by night in a very picturesque manner. Its beauty, 
 however, did not atone for the wastefulness of this 
 arrangement. Those flames were, in fact, valuable 
 gases burning uselessly, so now they are led away 
 and form a valuable asset to the works. 
 
 In order to do this the top of the furnace is partially 
 closed by a sort of basin with a large hole in the 
 centre. Into this hole there fits a cone-shaped plug, 
 the point of the cone being upwards and the plug 
 being held up by means of a chain. The ore, fuel 
 and limestone are tipped into the basin until it is 
 full, and then the plug is lowered for a moment to 
 allow them to fall into the furnace. The plug is 
 immediately raised again, so that except for those 
 brief intervals when the furnace is actually being 
 charged the top of it is closed. The gases which 
 would otherwise ignite and form flames at the top 
 (which, indeed, they do when the charge is being 
 dropped in) are led away through a huge pipe. 
 What, then, is done with them ? 
 
 Often they are burnt in the furnaces of boilers for 
 
 126 
 
HOW RAILS ARE MADE 
 
 raising steam for the steam engines. They are also 
 used to heat the blast for the furnaces. In some 
 cases they are used to drive enormous gas engines. 
 In some works they cannot profitably employ the 
 huge quantities of this " blast furnace gas " which is 
 available, and subsidiary industries have been, or 
 may well be, added to the works in order not to 
 waste them. 
 
 Let us now return to the iron. It flows from the 
 furnace along a spout on to the pig bed, a bed of 
 sand in which grooves have been made. These 
 grooves are filled by the iron which, when it has set, 
 becomes what is known as pig iron. This can be re- 
 melted in a cupola and used to make castings as 
 described elsewhere, or it can be taken to the steel- 
 works for making steel. At this stage, let it be 
 remembered, the iron contains about two per cent 
 or more of carbon, besides other impurities, such as 
 sulphur, phosphorous, silicon and so on. It is fairly 
 hard, but compared with the other forms of iron 
 and steel it is brittle. It is the material of which the 
 first metal " plates " were made for the primitive 
 horse railways. 
 
 These " cast-iron " plates were, it will be remem- 
 bered, succeeded by " rails " of " wrought iron." 
 This material is tough ; unlike cast iron it can be 
 bent ; it cannot be melted, but it can be softened 
 by heating and then shaped by hammering or by 
 passing between grooved rollers. It is less prone 
 to rust than is mild steel and it can be welded, but 
 in almost every other respect the newer " mild 
 steel " is superior. 
 
 127 
 
HOW RAILS ARE MADE 
 
 In order to change pig iron into wrought iron the 
 pig iron is melted and kept liquid in a special kind 
 of furnace, called a " puddling furnace." This is 
 not a large structure and may be described as a 
 shallow bath of fire-brick with a furnace attached, 
 things being so arranged that the flames from 
 the fire play upon the metal as it lies in the 
 bath. 
 
 A workman, called a " puddler," then stirs the 
 metal about with a rod, thereby exposing it to the 
 action of oxygen and causing the carbon to be 
 gradually burnt out of it. Now the reduction of 
 the carbon raises the melting point so that as the 
 metal loses carbon it becomes less fluid, and finally 
 adheres in the form of a lump to the end of the 
 stirrer. The puddler thus forms lump after lump 
 of de-carbonized metal, each lump as formed being 
 drawn out of the furnace. The lumps are at the 
 next stage heated again, hammered together into a 
 larger lump, which again is passed between grooved 
 rollers and thereby formed into bars of whatever 
 shape may be desired. The oxides which form on 
 the surface of the lumps, and certain other im- 
 purities, cause these bars when rolled to be of a 
 fibrous nature, the fibres running lengthwise of the 
 bar. Thus wrought iron has a texture almost like 
 that of wood and, again like wood, it has less strength 
 across the grain than with it. Still, it was and is 
 still to a less degree, a very useful material to which 
 the railway owes a great debt. Of it all rails were 
 made for many years, certain things, such as rivets, 
 are made still, and it is even now preferred for bridges 
 
 128 
 
SAWING COLD STEEL. 
 
 The remarkable machine illustrated here is described in the text. The article 
 to be cut is fixed upon a moving table and moved against the saw. The saw is just 
 a disc of steel plate and it cuts through material even harder ihin itself because of its 
 high speed of rotation. (Photographed at the L. & N.W.R. Works, at Crewe). 
 
HOW RAILS ARE MADE 
 
 by some engineers on account of its superior rust- 
 resisting powers. 
 
 Now we come to the steel of which rails are 
 made to-day and are likely to be made for many 
 years to come, since no rival material is yet in 
 sight. 
 
 There are two methods of making this steel, one 
 called the " Bessemer " process, after its inventor, 
 Sir Henry Bessemer, and the other the " open- 
 hearth " process. 
 
 The Bessemer process is carried on in a curious 
 kind of " fuel-less " furnace called a " converter." 
 It is a huge steel pear-shaped vessel, lined with non- 
 fusible sand and mounted, like the kettles which 
 sometimes grace the tea-table, upon " trunnions," 
 so that it can easily be turned over on to its 
 side. 
 
 When in this position molten pig iron is brought 
 along and poured into it. One may be inclined to 
 ask, why, if it be on its side, does not the iron run 
 out again ? and the answer is that its comparatively 
 narrow neck enables it to hold a certain amount of 
 liquid even when on its side. 
 
 Next the blast is turned on and air begins to blow 
 violently through holes in the bottom of the con- 
 verter, which is then turned into an upright position, 
 so that the air blows up through the metal. This 
 causes the carbon to be burnt out and, in fact, renders 
 it practically free from carbon, too free for practical 
 purposes. There is, therefore, added, after the blow- 
 ing has ceased, a quantity of a special sort of pig 
 iron containing a known amount of carbon. Thus, 
 i 129 
 
HOW RAILS ARE MADE 
 
 to put it simply, all the carbon is first burnt out and 
 then the correct quantity of it is put back. 
 
 The strange feature about this which gave rise 
 to the term " fuel-less furnace," used just now, is 
 that although no visible fuel is used the metal comes 
 out of the converter hotter than it goes in, the 
 carbon actually contained in the pig iron forming 
 the fuel which brings about this result. 
 
 This method is quick, but for that very reason 
 difficult to control ; hence Bessemer steel is sometimes 
 a trifle suspect as regards its quality. The rival 
 process is much slower, samples can be taken from 
 time to time and subjected to tests ; hence it is on 
 the whole more reliable. 
 
 Imagine an enormous bath holding perhaps 50 
 tons of molten iron. The bath itself and the low 
 roof over are formed of fire-brick with linings of 
 infusible sand. Over the metal there play huge 
 flames coming apparently from nowhere. The 
 mystery is explained by the fact that the furnace 
 is fired by gas and not by solid fuel. The coal or 
 coke is changed into gas in a plant called a " gas- 
 producer " situated near by, and the gas is led 
 through great flues of brickwork into the furnace. 
 It must not be supposed that this is coal gas such 
 as we burn in our houses ; it is " producer " gas, 
 practically the whole of the fuel being changed into 
 a gaseous form. It is not clean enough for domestic 
 use, but on the other hand coal gas would be too 
 expensive for making steel. 
 
 Arriving in the furnace through the flues at one 
 end the gas mingles with air from another flue and 
 
 130 
 
HOW RAILS ARE MADE 
 
 thereupon bursts into flame, the low roof of the 
 furnace being so shaped as to throw the heat down 
 upon the metal as much as possible. 
 
 The waste gases, the " burnt " gases we mi;;ht 
 call them, pass out through flues at the opposite 
 end of the furnace, and in this connection we see 
 a beautifully simple example of how to save 
 waste. 
 
 These furnaces are called " regenerative " because 
 a lot of the heat of the waste gases is caught and 
 brought back again into the furnace. The outgoing 
 gases traverse a series of flues which lead them 
 through chambers filled with loosely stacked bricks. 
 The gases, passing between and among these bricks, 
 give up a great deal of their heat, making the bricks 
 hot instead. When this has been going on for a 
 time and the bricks are very hot, the course of the 
 gases is reversed and the fresh gas and the air to 
 burn with it enter through the hot chambers. Doing 
 so, they pick up heat from the bricks and bring it 
 back into the furnace, in their turn heating up the 
 bricks on the other side. Thus the new gas and air 
 are continually restoring to the furnace heat which 
 the waste gases have just taken out. The reversal 
 of the course of the air and gas goes on at intervals 
 all the time the furnace is at work. 
 
 If you open the door of one of these furnaces and 
 attempt to look in with naked eyes you can see 
 nothing. If, however, you put on dark spectacles or 
 look through a sheet of dark glass you see a most 
 beautiful spectacle, a lake of liquid gold. As ore or 
 other materials are thrown in the liquid splashes 
 
HOW RAILS ARE MADE 
 
 about with effects far more beautiful than the finest 
 fireworks. 
 
 But how does all this change the iron into steel ? 
 
 It is done by the addition of suitable quantities 
 of a kind of iron ore called " hematite," which 
 contains a lot of oxygen. The oxygen from this ore 
 combines with the carbon in the rest of the iron and 
 both leave the furnace in the form of carbonic acid 
 gas. By the proper manipulation, therefore, of the 
 furnace, and the addition of the right quantities of 
 hematite, the desired percentage of carbon in the 
 whole mass of metal can be attained. And the 
 process is sufficiently slow to permit of samples 
 being taken from time to time to ensure that all is 
 as it should be. 
 
 Each of these processes is again divided into two, 
 described as " acid " and " basic " respectively. It 
 is only necessary to mention these in case the reader 
 has seen them referred to and would like to know their 
 meaning. The difference is in the material with 
 which the furnace or converter, as the case may be, 
 is lined. Each has the power of absorbing and so 
 removing from the metal some impurity. For 
 instance, some forms of pig iron contain a high 
 percentage of phosphorous, an element which is 
 fatal to good steel. By giving a " basic " lining to 
 the furnace or converter this is extracted from the 
 metal, and thus ores which would otherwise be 
 useless can be turned into good steel. 
 
 The steel industry of Germany in particular 
 benefited from the invention of the basic process, 
 for there are vast supplies of ore in Lorraine and 
 
 132 
 
HOW RAILS ARE MADE 
 
 Luxemburg which were till then useless. For this 
 process to work well the percentage of phosphorous 
 in the ore needs to be fairly high to commence with, 
 and then it is doubtful if all is got rid of ; hence 
 basic steel is not quite so reliable as that made by 
 the " acid " process. 
 
 When a basic furnace or converter is re-lined the 
 material of the old lining is ground up and then 
 forms the familiar chemical manure known as 
 " basic slag." 
 
 However it may be made, the steel when ready is 
 run off into tall rectangular iron boxes called " ingot 
 moulds." The moulds are open at both ends and 
 stand upon an iron floor. When set the steel thus 
 forms an ingot. 
 
 At this stage we must notice the very wonderful 
 machines with which a modern steelworks is equipped. 
 They belong, as it might be expressed, to the crane 
 family, but they are not simple cranes, being each 
 designed for a particular operation. Take the case 
 of a " stripper." It runs on lines overhead, just 
 like the overhead travelling crane to be seen in so 
 many large works where heavy things have to be 
 handled. Its duty is to remove the moulds from the 
 ingots ; for you must remember that the mould 
 for, say, a 3-ton ingot (an average size) is itself no 
 light weight. So the stripper lays hold of the mould 
 and pulls it upwards ; but not only that, at the same 
 time it pushes downwards upon the ingot itself, 
 lifting the mould, but holding the ingot down ; thus 
 there is no chance of the ingot sticking in the mould 
 and being carried away in it. 
 
HOW RAILS ARE MADE 
 
 The furnaces, too, which we were considering just 
 now, are attended by a mechanical attendant which 
 picks up half a ton of materials and puts it into the 
 furnace as easily as a man might throw in a handful. 
 When a quantity of material needs to be put into 
 the furnace it is first placed in a big, strong, steel 
 box ; then the machine puts forth its arm in an 
 almost human manner, takes the box, carries it 
 along, thrusts it into the furnace, turns it over, 
 withdraws it empty and takes it back again for more. 
 
 At later stages it is necessary to place ingots and 
 other heavy masses of metal in furnaces to be re- 
 heated, and here another type of " charging machine " 
 comes into play. It has not only an arm, but a hand. 
 It can pick up a large ingot between thumb and 
 finger, place it in or take it out of a furnace, as may 
 be necessary, and carry it about from place to 
 place. 
 
 These machines, although now largely constructed 
 in Great Britain, were first introduced in the United 
 States, where the shortage of skilled workmen has 
 brought out so many labour-saving devices. Apart, 
 however, from the saving of labour (thereby meaning 
 saving of expense) there is a humanitarian aspect. 
 The handling of these great hot masses by human 
 hands, while in many cases possible, is work which 
 no human being ought to be asked to do. It is too 
 wearing, and to do it for long almost de-humanizes a 
 man. Hence these wonderful machines, controlled 
 by man, but actually worked by electric motors, 
 confer a twofold benefit upon humanity. 
 
 But we must get on. We have reached the point 
 
 134 
 
HOW RAILS ARE MADE 
 
 where an ingot has been cast and the mould removed 
 by a stripping machine. It now requires to be re- 
 heated, so a machine picks it up and carries it away 
 to a furnace. This is in some cases under the floor, 
 so that the ingot is just dropped in, in a vertical 
 position ; or it may be like an elaborate form of the 
 domestic oven. The underground type of furnace 
 is called a " soaking pit," since the ingot needs to 
 be thoroughly soaked through with heat and equally 
 softened throughout. 
 
 Then it is lifted out and passed through a suc- 
 cession of " rolling mills," machines which are in 
 principle nothing more than the domestic mangle, 
 but with grooves cut in their iron rollers. 
 
 At each rolling the width and depth is reduced and 
 the length increased, until at last the ingot has been 
 rolled down into the familiar shape of the railway 
 rail. Of course, a single ingot will make more than 
 one length of rail, so that as the rolling goes on and 
 the bar lengthens it has to be cut several times, an 
 operation performed by a circular saw. 
 
 In travelling to and fro through the rolling mills 
 the steel moves upon what are termed " live rollers," 
 paths formed of iron rollers let into the floor and all 
 driven round by a motor. Thus the piece of steel 
 on issuing from one mill travels automatically upon 
 the rollers for some distance. If, then, as is probable, 
 it needs to go back through the same mill, but 
 through a different groove (for there are a series 
 of grooves upon the rolls in a single mill) the rollers 
 are reversed and the steel starts back again, being 
 guided by men with tongs into the fresh groove. 
 
HOW RAILS ARE MADE 
 
 Meanwhile, the rolling mill itself has been reversed, 
 and through the piece of metal goes. Having finished 
 at one mill the rollers carry it quickly along to the 
 next, and so, from the time it leaves the re-heating 
 furnace, passes through all the rolling operations and 
 finally emerges as rails, only a few minutes is occupied. 
 Thus we have traced the life history of a steel rail 
 from the ironstone quarry until the time when it is 
 ready to be used. 
 
 136 
 
CHAPTER X 
 THE STORY OF THE BRIDGES 
 
 IT is a great mistake to think that the big ex- 
 ceptional bridges are the only interesting ones. 
 On the contrary, the little ones, the everyday 
 ones, so to speak, have an interest all their own. 
 
 Has it ever occurred to you that these despised 
 things are by far the most important ? Look at it 
 this way. Take away the Forth Bridge. The North 
 British Railway would still be able to carry on. 
 Certain trains would have to go by a longer route 
 and it might be necessary for some people to use a 
 ferry, but the work of the railway could go on. 
 Suppose, however, that all the little bridges all over 
 the line were to disappear ; the ones that span 
 roads and streams, lanes and ditches ; the railway 
 would then for all practical purposes cease to exist. 
 
 So this chapter will be devoted to the little bridges. 
 
 Railway engineers divide bridges roughly into 
 two classes, " under-bridges," which are actually 
 underneath the rails, and " over-bridges," which 
 carry something else across the line. Of these the 
 under-bridges are naturally the most interesting to us. 
 
 Bridges are again divided up in another way 
 according to the way they are made. We will take 
 these one at a time. 
 
THE STORY OF THE BRIDGES 
 
 First of all there is the " plate-girder " bridge, 
 commonly used to span ordinary roads. It is so 
 called because it is built up of girders made largely 
 of steel plates. 
 
 But what is a girder ? you ask. It is another name 
 for a beam, the custom having arisen of saying beam 
 when it is of wood, but girder when it is made of 
 iron or steel. 
 
 A plate-girder, if it were sawn in two and then 
 looked at endwise, would look like a huge letter I. 
 The vertical part is the web and the two horizontal 
 parts are the flanges. The strength resides mainly 
 in the flanges, the chief duty of the web being to 
 hold the other two together. 
 
 The commonest form of bridge consists of three 
 of these girders with their ends supported on brick 
 piers. The main girders lie parallel, shorter ones, 
 called cross girders, filling in at right angles. Upon 
 the cross girders longitudinal sleepers of wood are 
 placed, and upon them the rails are fixed. Thus 
 each line of rails runs between two main girders, 
 the middle one of the three being made doubly 
 strong because it may be called upon to carry two 
 trains at once, while the outer ones cannot have to 
 bear more than one. The weight of the train falls 
 firstly upon the timber sleepers, and is by them dis- 
 tributed on to the cross girders, the ends of which 
 are in turn held up by the main girders. 
 
 These bridges are not made by the dozen all 
 alike, but each has a history, a personality of its own, 
 so to speak. It commences in the engineer's drawing 
 office at the head-quarters of the railway. The order 
 
 138 
 
THE STORY OF THE BRIDGES 
 
 goes forth to the steelwork section of the office that 
 a bridge is required at a certain place, and then an 
 expert draughtsman sets to work to design it. The 
 length is fixed for him by the width of the road, the load 
 which it will have to carry is a string of the heaviest 
 locomotives which the line possesses or is ever likely 
 to possess. It is very unlikely that an ordinary 
 bridge over a road will ever be crowded as full as 
 it can be with the heaviest engines, but such a thing 
 is possible and must be provided for. He knows 
 the width necessary to carry two lines of track, and 
 with these three items of information to go upon 
 he sets to work. 
 
 Some of his points he knows by heart. For example, 
 experience has shown that the most suitable height 
 for a girder is one-twelfth of its length, so if there 
 be no special reason to the contrary he makes his 
 main girders as many inches in height as they are 
 feet in length. 
 
 The other details he works out by mathematics, 
 in many cases using formulae which are known to 
 all designers of bridges, in other more difficult cases 
 using diagrams wherewith to find out the stresses 
 in certain parts, in other cases still calling upon his 
 experience. In one way and another, then, he builds 
 up the design on paper until a carefully finished 
 drawing is complete. 
 
 Ultimately copies of this drawing, or rather, one 
 ought to say these drawings, for there are always a 
 number of them showing different views, find their 
 way to a works where the bridge is to be made. 
 
 The drawings are made to some convenient scale, 
 
THE STORY OF THE BRIDGES 
 
 but at the works the parts are drawn out actually 
 full size, in chalk, upon a floor. Then a template 
 is made of each part in thin wood. A template 
 might be called a full-sized representation in wood 
 of what the iron part will be like w r hen it is finished. 
 As has already been said, the web is made of plate, 
 the flanges are made of one or more plates, frequently 
 one at the ends where the stresses are least, but 
 several plates piled one on top of another where the 
 stresses are greatest, in the centre. It is interesting 
 to note that the stresses in the flanges and in the 
 web so work out that the flanges have to be thickest 
 in the middle, but the web has to be thickest at the 
 ends. Then the flanges have to be connected to the 
 web by means of " angles," bars which viewed 
 endwise look like a letter L. 
 
 There are limits, of course, to the length which 
 plates and bars can be made, and so joints have to 
 be formed in places, which is done by butting the 
 two pieces together and then covering the place 
 with another similar plate or bar of short length. 
 
 Then, again, the tendency of the train when it 
 passes over a bridge is to crumple the web up, and 
 to stiffen it there are usually a number of vertically 
 placed angles which, because of their purpose, are 
 called " stiffeners." 
 
 All this has been explained to show why the bridge 
 builders go to the trouble and expense of drawing 
 the parts out full size and then practically making 
 each part in wood before it is made in iron. 
 
 All the different parts mentioned have to be con- 
 nected to other parts by rivets. The holes in one part 
 
 140 
 
THE STORY OF THE BRIDGES 
 
 must correspond accurately with the corresponding 
 holes in another part, and a slight error in one lot 
 of holes might easily cause a costly piece of steel 
 plate to be wasted. So templates are made first, 
 just the correct size, with every hole in its right 
 position. These templates can then be compared 
 and tried together, inaccuracies can be put right and 
 adjustments made, so that when, finally, they are 
 copied in steel the steel parts can be relied upon to 
 fit each other. 
 
 It needs a very skilled man to make the tem- 
 plates, but when they are finished satisfactorily he 
 can hand them over to a less skilled man, who will 
 mark off the plates and bars of steel according to 
 the templates, which bars and plates will then pass 
 on to less skilled men still, who will cut them and 
 punch holes in them according to the marks. 
 
 The parts, having been thus prepared, are then 
 put together much as a boy puts " meccano " parts 
 together, and fastened temporarily with bolts and nuts. 
 
 Work of this description used to be done mostly 
 in the open air, whence arises the fact that a place 
 where bridges are made is often called still a bridge- 
 yard. Nowadays, however, the yards are mostly 
 covered in, at any rate by a roof, although the sides 
 are often left open. This enables work to be carried 
 on in all weathers. 
 
 The roof is always a high one, to accommodate 
 an electric overhead crane. Not only is the crane 
 driven by electricity, but sometimes it has a magnet 
 in place of a hook for lifting the plates and other 
 parts about. 
 
 141 
 
THE STORY OF THE BRIDGES 
 
 There is not a great deal of other machinery. There 
 are usually rows of drilling machines for drilling holes, 
 punching machines for punching holes (where such 
 are permissible), shearing machines for cutting 
 plates, and in modern works a machine called a 
 " cropper," the function of which is to cut bars, 
 also various saws. 
 
 The drilling machine is well known and needs no 
 description. The punching machine is a very simple 
 contrivance ; a steel punch goes up and down 
 continuously, entering at the bottom of its stroke a 
 round hole in a steel die ; the plate or bar to be 
 punched is just slipped under it when it rises, and 
 on descending it pushes a little round disc of metal 
 through the hole in the die. Punched holes are not 
 so clean or so accurately placed as drilled holes. 
 
 The shearing machine is similar to the punching 
 machine, except that instead of a punch there is a 
 steel blade which rises and falls against another 
 blade much as the two parts of a pair of scissors 
 move against each other. A piece of steel inserted 
 between the two blades suffers the same fate as a 
 piece of paper between the blades of a pair of scissors. 
 
 The cropper is a special kind of shears which cuts 
 off bars of all shapes just as easily as the ordinary 
 shears cuts plates or flat pieces. 
 
 The saws used are generally of the circular variety, 
 in principle identical with that to be seen in carpentry 
 shops. A steel disc with teeth cut in the edge turns 
 round in contact with the object to be cut. In the 
 case of the metal saw the speed is much slower than 
 with the wood saw, and the saw is kept cool by a 
 
 142 
 
THE STORY OF THE BRIDGES 
 
 constant stream of soapy water driven on to it by a 
 little pump. 
 
 There is, however, one very remarkable machine 
 sometimes to be seen in bridgeyards known as a 
 high-speed sawing machine. The ordinary saw is 
 of hard steel, and it cuts the softer steel because of 
 its hardness ; if it were not hard it would not cut ; 
 moreover, it is never allowed to get hot, for if it did 
 it would become softened and unable to do its work. 
 
 In this strange machine, however, the saw disc 
 is of soft metal, and it is allowed to get as hot as it 
 likes. It is a well-known fact that if two things are 
 rubbed together they become hot, and that fact 
 which is a nuisance in most saws is actually turned 
 to valuable account in this one. The saw, rubbing 
 against the object to be cut, makes it soft because of 
 the heat which is generated. The saw itself, whizzing 
 round in the air all the time, does not suffer this 
 softening as the stationary object does and so it is 
 able to rub its way through. Acting in this manner 
 a disc of soft steel can cut through a piece of the 
 hardest steel ; probably the only case in which a 
 thing cuts something harder than itself. 
 
 But we must get on. When all the parts have 
 been put together and secured temporarily with 
 bolts the latter have to be taken out one at a time 
 and rivets put in their place. It may be wondered 
 why this should be necessary, and the reason is 
 twofold. First, a bolt and nut may shake loose, 
 which a rivet can never do ; and second, unless 
 carefully fitted at considerable cost the bolt never 
 quite fills the holes, whereas a properly driven rivet 
 
 143 
 
THE STORY OF THE BRIDGES 
 
 does. It is easy to see that unless the holes be 
 entirely filled there will be a little " play," which 
 will get worse and worse until the bridge might even 
 fail as the result. 
 
 There are three methods of doing this very im- 
 portant work of riveting. One is by hand. Three 
 men and a boy form a " squad " ; the boy " hots " 
 the rivets in a little forge and throws them across 
 to one of the men, the " holder-up." This man 
 inserts each rivet as he receives it in a hole, pushes 
 it right in, then holds it in with a heavy hammer. 
 The other two men then attack the end which 
 projects at the other side, first of all hammering it 
 down well into the hole to ensure the hole being 
 filled, then hammering over what still projects in 
 such a manner as to form a rough head, and finally, 
 one man throwing aside his hammer and holding 
 a cup-shaped tool over the roughly formed head, 
 which tool is then hammered down by his mate, 
 a nicely shaped head results. 
 
 The second method is by the use of a pneumatic 
 " pistol " hammer, as described in connection with 
 the visit to a locomotive works. 
 
 The third way is to use what the workmen call an 
 " iron man." This may be described briefly as an 
 enormous thumb and finger which, actuated by 
 hydraulic pressure, just squeeze the rivet into shape. 
 
 The observant traveller will probably have noticed 
 that many small bridges, such as those now under 
 discussion, have no cross girders, or rather that these 
 girders take the form of steel troughs attached 
 together so that they constitute a continuous floor 
 
 144 
 
THE STORY OF THE BRIDGES 
 
 all over the bridge. This " trough-flooring," as it is 
 termed, is made by pressing steel plates in a powerful 
 hydraulic press. 
 
 Of course, even when the bridge is finished in the 
 works there are still a number of holes filled only 
 with bolts or else quite empty, for the bridge will 
 have to go to its destination in parts and be put 
 together there, the final riveting being done on the spot. 
 
 In many respects this placing in position is the 
 most romantic incident in the bridge's history, as 
 the following actual descriptions will show. 
 
 When a line is first made the bridges are taken 
 along in parts either by lorries on the road below, 
 whence they are hoisted into position, or else they 
 are taken along on the partly finished line above. 
 In either case the work can be done in the daytime 
 and more or less at leisure. When, as is often the 
 case, the bridge is to replace an older one in an 
 existing line, the work has to be done at night or on 
 Sunday afternoon, between trains, the traffic going 
 on all the time just as if nothing were happening. 
 
 Success is then possible only as the result of the 
 most careful preparations. Everything has to be 
 thought out beforehand down to the smallest detail, 
 for the lack of, say, a single tool might throw the whole 
 thing out of gear, the favourable interval in the traffic 
 might be missed and the whole programme have to 
 be postponed for a week. 
 
 The first bridge that we will think of was on one 
 of the best known English lines, over a main road 
 connecting two towns ; it carried two lines of railway 
 with a fairly continuous traffic. 
 
 K 145 
 
THE STORY OF THE BRIDGES 
 
 The old bridge was made of cast iron, a type of 
 construction never used now, as cast iron is not 
 considered reliable enough to withstand the heavy 
 shocks caused by the passage of modern locomotives. 
 
 The first thing to be done, therefore, was to get 
 the old bridge out, and for this purpose a staging 
 of timber was built beneath it. It would be almost 
 true to say that a temporary bridge of timber was 
 built underneath the other one. When this temporary 
 bridge was finished wedges were driven in between 
 the cross girders of the old bridge and the temporary 
 one, so that after having carried the line for fifty 
 years or so those old cast-iron girders were at last 
 relieved of their load. The cross girders were then 
 disconnected from the old main girders until, one 
 Saturday night, they were taken right away. 
 
 Saturday night was chosen because there was 
 then the least traffic. What there was was diverted on 
 to one line, so that for a few hours trains were passing 
 both up and down over the same rails. To prevent 
 any danger of collision, an official with a white band 
 on his arm travelled on every engine which passed. 
 He was a sort of human substitute for a staff. No 
 train was allowed to move on to the line unless he 
 was on it. 
 
 A big crowd of workmen were there, brilliant flare 
 lights were lit, officials were there to represent the 
 different departments of the line. The travellers 
 by the passing trains may well have wondered what 
 was the matter. 
 
 As soon as the trains had all been diverted to one 
 line the men started to attack the old road and to 
 
 146 
 
THE STORY OF THE BRIDGES 
 
 pull up the rails. Then, at the first considerable 
 interval between two trains, an engine brought a power- 
 ful crane and some trucks along. The crane quickly 
 picked up the big centre girder, placed it on a truck 
 and then the line had to be cleared for another train. 
 
 Thus, at intervals two of the main girders were 
 removed and also the cross girders from under one 
 line, which was then re-laid upon the temporary 
 bridge and the double line working restored. The 
 whole operation took less than six hours. 
 
 In like manner, the next Saturday night was 
 employed in removing the third cast-iron girder, 
 and in addition the new girders were brought along 
 on trucks and dropped by two cranes, one holding 
 each end, into position. Two more Saturday nights 
 were spent, one in slipping the new cross girders into 
 position, the other in putting in rivets which could 
 not be got in during the week. 
 
 Then the temporary wooden structure was taken 
 away and the new bridge stood finished and complete. 
 
 Where bridges have to carry only a light load the 
 solid " web " is often replaced by a light lattice 
 work. This form of structure is very popular for 
 footbridges. The name lattice girder is applied to such. 
 
 The writer was once responsible for the fixing of 
 two lattice girders to carry a signal cabin above a 
 main line just out of London. There were twelve 
 pairs of rails under this bridge, and the longest 
 interval between trains was about forty-five minutes 
 in the small hours of Sunday morning. The girders 
 were 90 ft. long and 12 ft. deep. Since, of course, 
 the underside of them had to be high enough to 
 
 14? 
 
THE STORY OF THE BRIDGES 
 
 clear the traffic, the upper edge was about 25 ft. up 
 in the air, far above the reach of any travelling crane. 
 They had, therefore, to be lifted by means of a 
 " derrick," a huge timber 40 ft. long and 10 ins. 
 square, with pulley blocks lashed to its upper end. 
 
 The mere raising of this timber was in itself no 
 small matter, but it was managed during the week 
 by lashing some blocks to a conveniently placed 
 telegraph pole. Then when the time came it had to 
 be gradually " walked," as the workmen call it, from 
 the side of the line to the centre of the twelve roads. 
 By " walking " a derrick is meant sliding the foot of 
 it along inch by inch, while men let out some of the 
 guy ropes and pull in others in order to keep it upright. 
 
 Eventually the rope was attached to one of the 
 girders, passed up to the pulley blocks at the top of 
 the derrick, down again to a block at the foot of the 
 derrick and then to a locomotive. 
 
 This hoisting by means of a locomotive, particularly 
 in the middle of the night, is an exciting business. 
 The foreman gives the word, the engine starts to 
 move and so to pull the rope, things creak, chains 
 suddenly settle down to their various jobs with a 
 crack, you see the girder rising from the ground, and 
 inevitably, especially if you are in any sense re- 
 sponsible, the thought comes, " suppose something 
 broke." All concerned breathe more freely when 
 the thing is at last securely fixed in its place. 
 
 When a pair of girders have to be lifted like this 
 (and there are always two) the second one is worse 
 than the first, because the first gets in the way. So 
 it all has to be planned out mentally beforehand, 
 
 148 
 
THE STORY OF THE BRIDGES 
 
 or on paper, to make quite sure that everything will 
 come right. 
 
 It is not only light bridges which are of the lattice 
 structure. There is one, for instance, near where 
 these words are being written, across a very wide 
 road and carrying the heaviest main line traffic, 
 which is of the lattice type. 
 
 The reason for this is that it is too big for a simple 
 web of plates. Plates are not made large enough to 
 work conveniently, and even if they were it would 
 be found more economical in such a large bridge to 
 place the plates, reinforced by angles, in a lattice 
 arrangement rather than as in plate-girders. 
 
 Thus we may say that for under-bridges of small 
 or moderate size the plate-girder bridge is best, for 
 very large bridges or for bridges to carry light loads 
 the lattice form is best. 
 
 There are many cases, particularly in large bridges, 
 where the upper side of the girder is given the form 
 of an arch. Those are spoken of as " bowstring " 
 girders, from their similarity to the bow of an archer. 
 
 The science of bridge design is so well understood 
 now that very often bridges are not tested, but in 
 some special cases they are tried in the following 
 simple manner. A wooden rod is fixed in some 
 convenient way against the centre of the bridge and 
 a mark is made upon it showing the level of the bridge. 
 Then some heavy locomotives are made to stand upon 
 the bridge and the amount of bending which takes place 
 is noted. Very seldom is anything found to be wrong. 
 
 So when you go on a railway journey, the last thing 
 you need be anxious about is the safety of the bridges. 
 
CHAPTER XI 
 HOW SINGLE LINES ARE WORKED 
 
 BY " single " line is meant not that the trains 
 run on one rail, as has been proposed in the 
 " mono-rail " schemes, but that trains run 
 both ways along a single pair of rails. 
 
 It is evident that such a line has dangers of its 
 own far more terrible in their possibilities than the 
 risks of ordinary double lines. 
 
 The obvious way to remove these special risks is 
 to make the lines double, to have one pair of rails 
 for up trains and one for down trains, but there are 
 many cases where the amount of traffic does not 
 justify such a large expense. 
 
 There are places, even in so densely peopled a 
 country as Great Britain, where only a few trains 
 are needed between two points, yet those few trains 
 may be quite important ones. In such cases a single 
 line is quite sufficient, and it would be simply a waste 
 to make it double. Some other means, therefore, 
 has had to be adopted to ensure safety. 
 
 In the first place, nearly every single line has short 
 lengths at convenient intervals where the line is 
 doubled in order to afford passing places where one 
 train may pass another. The problem, in those 
 cases, is to ensure there shall not be more than one 
 
 150 
 
HOW SINGLE LINES ARE WORKED 
 
 train at a time in the space between two passing 
 places, at all events not in the same direction. 
 
 The only exceptions are short branches, too short 
 to need any passing place, where safety is ensured by 
 having only one engine to work all the trains on 
 that branch. That is perhaps the simplest method 
 of all, but unfortunately it cannot be applied, except 
 in these comparatively few cases. 
 
 An arrangement often resorted to when, through 
 an accident or other emergency, a piece of line has 
 to be worked as " single," is to have a " pilotman," 
 as he is termed, a special official told off for the 
 purpose and distinguished by a band round his arm ; 
 a train is only allowed to move on to the single line 
 when this man is on the engine. 
 
 The same principle underlies the " staff " system, 
 which was the first system to be used on single lines 
 generally. 
 
 Under this there is for each section of single line 
 a special " staff," generally a metal rod, clearly 
 marked in some way with the name of the section 
 to which it applies. The rule, then, is that upon no 
 account whatever may a driver move a train on to 
 the section until he has the staff with him. 
 
 At each passing place he gives up the staff for 
 the section he has just left to the stationmaster or 
 signalman, and receives in exchange the staff for 
 the section which he is about to enter. 
 
 It will be seen at once that this arrangement is all 
 right so long as the trains alternate regularly, first 
 an up train, then a down train, all through the day. 
 But suppose, as must often happen, that several 
 
 15* 
 
HOW SINGLE LINES ARE WORKED 
 
 trains follow each other in the same direction without 
 one in between to bring the staff back, what 
 then? 
 
 This is overcome, in the following manner, by the 
 " staff and ticket " system. 
 
 At each passing place there is not only a staff, but 
 a box containing certain printed tickets. The staff 
 has, on one end of it, a projection which forms a key, 
 by means of which this box can be opened. If, 
 therefore, a signalman or stationmaster knows that 
 there will be two or more trains in the same direction 
 before one comes the other way, he may use the 
 staff to unlock the box and take out a ticket. This 
 he hands to the driver of the first train. He does 
 not give him the staff under these conditions ; he 
 shows the staff to the driver, but gives him the ticket. 
 Then the driver may proceed. 
 
 If there are more than two trains going in the same 
 direction, the driver of the second one is also shown 
 the staff and given a ticket, and so on until the last 
 of the series. To him the staff is given in the ordinary 
 way. 
 
 That arrangement is all right up to a point. It 
 has the disadvantage that a train may enter a section 
 before the preceding one is clear away, and so it 
 has to be worked in conjunction with telegraphic 
 messages between the two ends of the section, like 
 the block signalling on an ordinary double line. It 
 also has the disadvantage that if a train turns up 
 unexpectedly at the commencement of a section 
 when the staff happens to be at the other end it has 
 either to wait a long time for a train to bring the 
 
 152 
 
HOW SINGLE LINES ARE WORKED 
 
 staff, or for a man to bring it, either on foot or on 
 horseback. 
 
 Needless to say, a system with so great a draw- 
 back as this was not allowed to prevail for long before 
 someone found a means of avoiding the difficulty. 
 Hence arose the " tablet " system, the system which, 
 in one form or another, is now used on single lines 
 all over the world. 
 
 In this system there are two instruments for each 
 section of single line, one at each end, connected 
 together by wires, like two telegraph instruments. 
 They are exactly alike, consisting externally of a 
 wooden cabinet with certain knobs and indicators 
 attached, and together they contain a number of 
 tablets, usually thirty or thereabouts. 
 
 To understand how this works it is simplest to 
 regard the two instruments as forming really one, 
 linked together by the wire, and the construction is 
 such that only one tablet can be out at a time. As 
 soon as one has been taken out all the others at both 
 ends are securely locked up, and so they remain 
 until the one has been put back. A tablet may be 
 taken out at either end of the section and put back 
 at either end, but there can only be one out at a time. 
 
 This is then given to the driver as a sign that he 
 may proceed, and he must not proceed without it. 
 
 The tablets are little pieces of metal carefully 
 marked to show what section they belong to and 
 also numbered, so that each one can, if necessary, 
 be distinguished from any other. They also vary 
 slightly in shape, so that it is impossible to put one 
 into the wrong instrument. 
 
HOW SINGLE LINES ARE WORKED 
 
 If the flow of traffic is mainly in one direction the 
 result is that the tablets accumulate at one end, and 
 to deal with this it is arranged that when the number 
 at either end has fallen to a certain limit, say five, 
 the signalman advises the telegraph linesman, who 
 thereupon sets it right. This man is provided with 
 a key, by means of which he can take out the surplus 
 tablets from the end where there is an accumulation. 
 He can only do this subject to very special conditions. 
 He has to make a list of the tablets which he takes 
 out, noting the distinguishing number on each in a 
 book which he carries for the purpose. This has to 
 be countersigned by the signalman at the box where 
 he takes them out. He must on no account let them 
 out of his possession until he places them in the 
 instrument at the other end, and when he does 
 that he must get the signature of the signalman 
 there. At first sight it seems that the mere possi- 
 bility of any man being able to take out a handful 
 of tablets at once is a source of danger, but the 
 strict regulations and the exchange of signatures 
 with the two signalmen entirely remove this. 
 
 But we have not yet reached the last of the wonder- 
 ful precautions embodied in this system. There 
 are signals at the passing places on a single line, just 
 like those on a double line, and a driver has to observe 
 these even if he has a tablet in his possession. This 
 is intended to guard against, among other things, 
 a driver thoughtlessly proceeding without the 
 tablet. 
 
 On some lines these signals are normally locked at 
 danger and can only be unlocked by using the tablet 
 
 '54 
 
HOW SINGLE LINES ARE WORKED 
 
 as a key. Thus if the signal is lowered it is a proof 
 that the free tablet is at that end. There we have a 
 species of inter-locking between the tablets and the 
 signals. 
 
 Something similar is done where there are points 
 on a single line. It will be clear to anyone that there 
 must be places where the presence of a brickfield, a 
 stone quarry or something of that kind may necessi- 
 tate a siding in the middle of a stretch of single line. 
 How, then, can it be ensured that the points of such 
 a siding are always properly set for an approaching 
 train ? This is how it is done. 
 
 A train comes along which has trucks to put into 
 the siding, or which has to call to fetch trucks out. 
 Of course, the driver has the tablet with him. When 
 he approaches the points he stops, and the guard 
 gets down and to him the driver hands the 
 tablet. 
 
 Now the points are normally locked in the correct 
 position for trains to run straight along upon the 
 main line, so the guard has first to unlock them. 
 To do this he raises a spring, pulls out a slide from 
 the locking mechanism, puts the tablet into a cavity 
 in the slide and then pushes it back. 
 
 The points are now unlocked, but he has lost the 
 tablet. It is the tablet now which is locked up, for 
 when once he has moved the points for the train to 
 go into the siding he cannot pull the slide out again. 
 All is safe, therefore, and no other train can approach 
 from either direction while the points are open. 
 
 Having finished, the guard restores the points to 
 their normal state, when, and not before, he can 
 
HOW SINGLE LINES ARE WORKED 
 
 pull the slide out again and regain possession of the 
 tablet. The points must be right, therefore, before 
 another train can pass. 
 
 Having received the tablet back from the guard 
 the driver can then proceed upon his way. 
 
 The tablets are usually placed, when in use, in a 
 leather pouch with a large loop-shaped handle. The 
 purpose of this is to enable the man on the engine to 
 catch it upon his arm as he passes a passing place, 
 without having to stop. In some places this idea is 
 carried even farther, and the bag is hung upon a 
 post beside the line, so arranged that a projection 
 upon the engine catches it, in which case a fast train 
 can run past a tablet exchanging point without 
 stopping or even slowing up materially. By similar 
 means the tablet for the previous section can be 
 hung from the engine and left, after passing, hanging 
 upon a projection upon the post, so that the complete 
 exchange of one tablet for another is practically 
 automatic. 
 
 As has been pointed out already, a line may be 
 single because few trains travel over it, yet some 
 of those few trains may be quite important ones, 
 which it is desirable to run as fast as possible, so 
 that this tablet -changing device is very valuable. 
 
 There is a modification of the tablet system in 
 use at some points, called the " permissive tablet 
 system." This is specially useful where a section is 
 a long one, and it may be desirable to let one train 
 follow another fairly closely, at a shorter distance 
 apart than the length of that section. This would 
 be likely to occur upon a line serving a growing 
 
HOW SINGLE LINES ARE WORKED 
 
 district, where the conditions are being approached 
 which will make it worth while to double it. 
 
 In such a case the permissive tablet arrangement 
 permits a signalman who holds an ordinary tablet 
 to obtain another one of a different kind a " per- 
 missive tablet." 
 
 Having, then, several trains to pass through 
 quickly in the same direction he first obtains the 
 ordinary tablet. This enables him to obtain " per- 
 missive " tablets for the earlier trains, yet prevents 
 a train entering the section from the other end. The 
 last of the series takes the ordinary tablet. 
 
 This, it will be seen, is very similar to the staff 
 and ticket arrangement. 
 
 The later trains of a series are, of course, warned 
 to go carefully, prepared to stop short of any obstruc- 
 tion. 
 
 There is another system called the " electric staff " 
 system, but this is in all essential features similar 
 to the tablet. 
 
 '57 
 
CHAPTER XII 
 RAILWAY SIGNALS 
 
 THE earliest signals were formed by a man's 
 arm. We see the same thing even now 
 when a guard starts a train from a station. 
 Hence it was quite natural that when a permanent 
 signal mounted upon a post came into use it took 
 the form of an arm projecting out from the post 
 horizontally. 
 
 At first these arms had three positions, and it is 
 a very interesting fact, as we shall see later, that 
 after being abandoned and out of use for a great 
 many years, the three-position signal has come into 
 vogue again on certain lines. 
 
 These three positions were " horizontal," meaning 
 " stop," half down, at an angle of about forty-five 
 degrees, indicating " go on, but keep a careful look 
 out," and " vertical," which showed that the line 
 ahead was clear and that the driver might go on with 
 confidence. 
 
 The arms were then operated by levers at the foot 
 of the post, and the man often had nothing more 
 than a shelter, as a " fogman " has nowadays. 
 There was no need for a cabin then, apart from the 
 comfort of the signalmen (and such things were not 
 thought much about in those days), because there 
 
 158 
 
RAILWAY SIGNALS 
 
 were no instruments then. The signalman worked 
 to his watch and nothing more. 
 
 When a train passed him he noted the time ; after 
 a certain number of minutes had elapsed he put the 
 signal half-down ; after the lapse of a certain further 
 interval he let it right down. That was all he did, 
 and while it was thought at the time to be sufficient 
 we can easily see how easy it would be under such 
 conditions for accidents to happen. 
 
 As a matter of fact, little else was possible at that 
 time, for the electric telegraph had not been in- 
 vented and modern signalling is based almost entirely 
 upon the use of the telegraph. However railways 
 would have been worked if the telegraph had not 
 come along just in the nick of time, is an interesting 
 subject for thought. 
 
 Let us trace the development of the modern 
 signalling systems from these simple beginnings. 
 
 At first we may picture to ourselves the addition 
 of a simple " needle " telegraph instrument to the 
 signalman's outfit, enabling him to keep in touch 
 with his colleagues on either side and to learn from 
 them when trains duly reached them. With the 
 installation of these instruments came the need for 
 better shelter, leading eventually to the comfortable 
 and well-fitted cabin of to-day. 
 
 The use of the telegraph led almost inevitably to 
 the invention of the " block " system. A signalman 
 was instructed not to lower the signal for a train to 
 proceed until he had heard on the telegraph that 
 the previous one had safely reached the next 
 signals. There you have the basis of the " block 
 
RAILWAY SIGNALS 
 
 system," the chief cause of the safety of modern 
 trains. 
 
 Another thing which happened soon after the 
 signal was first installed in its primitive simplicity 
 was the discovery of interlocking. Who actually 
 invented this is somewhat of a mystery, but the 
 following story is given on the authority of an 
 official of one of the great British railways. 
 
 At a certain small station there was a level crossing. 
 This was protected by a tall signal worked by a 
 lever at its base. When the gates were open to road 
 traffic, and therefore closed across the railway, this 
 signal was supposed to be kept at danger. When 
 the gates were shut to the road and open to the 
 railway, then, and only then, was the signal allowed 
 to be lowered. It was the stationmaster's duty to 
 supervise this and see that it was done correctly. 
 
 Now a train used to come through that station 
 every evening at nine o'clock. It did not stop, so 
 that the stationmaster had no need to be there, 
 except to look after the working of the signal. 
 
 But nine o'clock was the hour when the excellent 
 stationmaster liked to have his supper, so that the 
 call of supper and the call of duty came into conflict. 
 
 Evidently this official was an ingenious man, for 
 he contrived, after a while, to have his supper at 
 the desired time without in any way endangering 
 the train or anyone else. 
 
 He noticed that if he fixed a stout bar to the gate 
 in a certain way, it would prevent the signal being 
 worked ; it would project itself just above the lever, 
 so that it could not be moved. 
 
 160 
 
By permission of the] 
 
 [Great Western Railway. 
 
 THE NEWEST KIND OF SIGNAL. 
 
 " Three-position " signals are now coming into extensive use. The one on the 
 right is at danger ; the one on the left is at " proceed with caution." To indicate 
 safety the arm goes straight up. The corresponding lamps are red, yellow and 
 green. The arm is worked by an electric motor in an iron case fixed to the post. 
 
RAILWAY SIGNALS 
 
 This, of course, happened only when the gate was 
 in one certain position, namely, open to the road. 
 
 Thus, so long as the gates were open to the road and 
 closed against the train the signal could not possibly 
 be lowered. Before it could be lowered the gates 
 had to be opened for the train. So the good station- 
 master was able to have his supper, knowing that his 
 assistant whom he had left in charge could not make 
 a mistake. 
 
 Even if that be not the true story of the origin of 
 " interlocking " it is quite .a good story and serves 
 to indicate very clearly what " interlocking " really is. 
 
 To-day that principle is applied to all sets of signals. 
 All those which need to be operated in connection 
 with others are so interlocked with them that they 
 cannot be pulled except in certain permissible com- 
 binations. Indeed, on some lines the apparatus in 
 one cabin actually locks and unlocks that in another 
 by electricity. But to that we will return a little 
 later. 
 
 So far we have traced the growth of the two great 
 underlying principles of signalling, first the " block 
 system," under which it is decreed that not more 
 than one train shall be between two signal cabins 
 at the same moment, and second, that the apparatus 
 in any one cabin shall be so interlocked that a careless 
 signalman simply cannot lower contradictory signals. 
 
 To both of these principles there is added another 
 one, without which neither would be perfect. This 
 third principle is that everything shall be so arranged 
 that failure of apparatus shall stop traffic rather 
 than endanger it. 
 
 L 161 
 
RAILWAY SIGNALS 
 
 This is well illustrated by the way a signal is 
 fitted up. Everyone is familiar with the heavy weight 
 on the end of a lever to be seen at the foot of every 
 signal post. The purpose of that is to keep the wire 
 taut. The signal is, of course, operated by a wire 
 from the signal cabin, and in order to lower the 
 arm the wire has to be pulled. One is apt to think 
 that the signalman lets the arm fall when the line 
 is clear, but that is not the case ; he actually pulls 
 it down by pulling up the balance weight. 
 
 Thus, should the wire break, the arm flies to 
 danger. Indeed, the principle is carried still further 
 
 OOVN DOWN HOME 
 
 STARTING DieTAHl 
 
 Fig. 9. DIAGRAM SHOWING THE NAMES or SIGNALS AT 
 A WAYSIDE STATION. 
 
 than that, for the arm itself is actually loaded at 
 its short end so that in the event of the rod connecting 
 arm and balance lever becoming detached, a most 
 unlikely thing, the arm itself will go to danger. 
 
 This result is attained by making the iron frame 
 which carries the coloured glass heavier than it 
 need otherwise be. 
 
 On some lines nowadays the same effect is attained 
 by making the signal arm go upwards instead of 
 down to indicate line clear. 
 
 Generally speaking, there is a signal cabin at 
 every station, and for each line there are generally 
 three signals. Near to the station on the side at 
 
 162 
 
RAILWAY SIGNALS 
 
 which the train enters, there is one called the home 
 signal. It is generally on the top of a tall post, for 
 it is the most important of the signals and may 
 need to be seen from a considerable distance by 
 trains which are not stopping at the station. 
 
 At the other end of the station there is a second 
 signal, usually on a short post, called the starting 
 signal. The third is the " distant " signal, and its 
 place is about 800 yards back, behind the home 
 signal. It is generally distinguished by having a 
 V-shaped notch cut out of the end of the arm. At 
 a distant signal trains do not stop, for it is only an 
 indicator to warn an approaching train if the home 
 signal is against it. Thus, if a distant signal is up, 
 or " on " as the railwayman calls it, the driver does 
 not stop, but slows down and keeps his train in hand 
 ready to stop at the home signal if need be. 
 
 The purpose of the starting signal is this : A train 
 is approaching a station where it is booked to stop, 
 but the section ahead is not clear, for the preceding 
 train has not yet passed the next cabin ; the signal- 
 man, therefore, keeps his home signal up until the 
 train has nearly stopped ; then he lowers it and 
 allows the train to draw slowly ahead up to the starting 
 signal. But for the latter he would have to keep it 
 standing outside the station until the section ahead 
 had become clear. 
 
 Where there is a long distance between two stations 
 there is often an intermediate signal cabin ; there 
 are also cabins at junctions where there are no 
 stations, but every cabin has a similar set of signals 
 for each line and for branches if there be any. 
 
 163 
 
RAILWAY SIGNALS 
 
 Moreover, every cabin is in electrical communication 
 with the cabins on either side of it, and is itself full 
 of wonderful devices of a mechanical nature to 
 prevent the signalman making a mistake. 
 
 At junctions or where there are cross-over roads 
 or sidings, the points as well as the signals are worked 
 from the cabin, and points and signals are inter- 
 locked so that they can only be worked properly 
 together. 
 
 Let us, in imagination, take a look inside an 
 ordinary typical signal cabin. Its main feature is 
 the row of strong steel levers. These are about the 
 right height for a man to pull easily, as, indeed, they 
 need to be, for a lever which operates distant points 
 calls for some good muscular effort to move it. 
 
 The levers are pivoted about the level of the floor, 
 and their upper halves are guided by a framework 
 of iron with slots in which they can move to and 
 fro. Each arm, also, is fitted with a catch which 
 holds it in position, except when the man is ready 
 to move it. 
 
 Above the row of levers is a shelf, the " instrument 
 shelf," upon which stand all the marvellous electrical 
 devices by which the signalman is assisted in his work. 
 
 Every instrument has its label setting out clearly 
 what it is for, and every lever has a little tablet 
 showing the signal or switch to which it relates. 
 The levers are grouped together, so that all those 
 likely to be pulled at the same time are near at 
 hand, and they are further distinguished from one 
 another by their colour, signals being one colour 
 and points another. 
 
 164 
 
RAILWAY SIGNALS 
 
 Below the floor is the interlocking apparatus, 
 one of the most beneficent pieces of machinery ever 
 invented. To it we will now turn our attention. 
 
 The basis of it is an oblong block of iron as long as 
 the row of levers and of a -width which varies in 
 different cabins, but may be put as somewhere 
 about a foot. 
 
 In the upper surface of this " locking trough," as 
 it is called, there are a number of grooves, some 
 long, running lengthwise, and some short, running 
 crosswise at right angles to the first. 
 
 In each of the short grooves there fits a steel 
 slide smooth of surface, and of such a size that it 
 fits nicely, and is, therefore, free to slide endwise, 
 but without shake. 
 
 It is not possible to describe this intelligibly 
 merely in words ; the aid of a series of three diagrams 
 is necessary. 
 
 In the first of them we have a representation of a 
 fragment of a locking trough and two short pieces 
 of slide. Everything is cut away, except what is 
 necessary to show clearly how this mechanism works. 
 Slide A it will be noticed has a notch cut in its right- 
 hand side, while slide B has a similar notch in its 
 left side. In one of the longitudinal grooves there 
 lies a short piece of steel called a lock, and in the 
 illustration it is shown with one end fitting into the 
 notch in slide A, while its other end is close up 
 against the edge of slide B. Now supposing someone 
 were to try to pull slide A, he would find it impossible 
 to do so, because of the lock engaging in the notch. 
 
 On the other hand, slide B is quite free. Suppose 
 
 165 
 
RAILWAY SIGNALS 
 
 it be pulled, so that we get the state of things shown 
 in the second. Now A is free, because when it is 
 pulled the lock is able to slide to the right into the 
 notch in B. 
 
 GROOVE FOR SJL1D1 
 
 GROOVE 
 FOR LOCK 
 
 LOCK 
 
 Fig. 10. This diagram shows the beautifully simple means 
 by which the signal levers are made to lock and unlock each 
 other, so that a signalman cannot make a mistake. 
 
 Slide A cannot be pulled because of the lock, but slide B 
 is quite free. 
 
 Suppose slide B to be pulled, then we get the position 
 shown in the next diagram. 
 
 Thus we get the position shown in the third, where 
 slide A is free, but slide B is locked, exactly the reverse 
 of what we started with. Therefore, slide A must 
 
 166 
 
RAILWAY SIGNALS 
 
 be restored to its first position before slide B can be 
 used again. 
 
 This is, of course, merely a simple illustration of the 
 principle. In actual application the various inter- 
 locking combinations are very complicated, and the 
 result of the most careful thought and consideration, 
 but however complicated they may be, when once 
 the necessary notches have been made in the slides 
 and the necessary locks put in position, the working 
 of the apparatus is beautifully simple. It is so simple 
 
 LOCK 
 
 U)CK 
 
 Fig. 11. 
 
 This shows how the pulling This shows how the pulling 
 
 of slide B unlocks elide A. of A locks B in the pulled 
 
 position. 
 
 that failure is, humanly speaking, an impossibility, 
 and the whole is so robust and strong that no signal- 
 man, no matter how muscular he may be, can possibly 
 pull " off " a signal which he ought not to do. 
 
 The lower end of each signal lever is connected 
 to a slide, so that the slide controls the movement of 
 the lever absolutely. 
 
 As an illustration of the effect of interlocking we 
 may take the case of a junction where a branch goes 
 off to the right in a " down " direction. A down 
 
 167 
 
RAILWAY SIGNALS 
 
 train in order to pass on to the branch will then have 
 to cross the "up " line, and unless great care were 
 exercised that point would be a source of great 
 danger, for a " down " train to the branch might 
 collide with an " up " train on the main line. 
 
 In such a case it is so arranged that the points 
 cannot be set for the " down " train to cross the 
 " up " line unless all the signals controlling the " up " 
 line are at danger, and further, as soon as the points 
 are so set, it is impossible for those signals to be 
 lowered. The interlocking apparatus effectually 
 prevents any error on a point like that. 
 
 All points the tongues of which point in the 
 direction from which a train reaches them are 
 called " facing points." For example, those on the 
 " down " line at our imaginary junction are " facing 
 points," but those on the " up " side would be 
 " trailing points." It is quite clear that the former 
 are much the more dangerous, for if not properly 
 set and tightly held they might easily throw a train 
 off the line, whereas if trailing points are not correct, 
 the train itself, in passing over them, will tend to 
 put them right. Great care is therefore taken to 
 ensure the proper working of facing points. In the 
 first place, there is one lever in the cabin for the 
 purpose of moving the points from one position to 
 the other ; then there is a second, the operation of 
 which locks them or unlocks them, as the need 
 may be. 
 
 If a signalman, then, wishes to alter the facing 
 points at a junction, he has, first of all, to unlock 
 them by moving one lever, then he sets them in the 
 
 168 
 
- 8 o 
 
 S-S-H^ 
 o ,. a ri 
 
 S ~ 
 
 S c o rt 
 
 ^li 
 
 .11 | 
 I Jg 1 - 
 
 "rt u 
 
 o c c 
 
 ">' 2f -S 
 
 ei:i 
 
 - a 
 
 | si 5 > 
 'S o ^ IH 
 
 O -M C ^ 
 
 1 a^-S 
 " o I 
 
 tiHJ 
 
 ! 1 S 
 
 a^ 
 
 2 
 3 
 
 T3 
 
 , 0| 
 
 S o 
 
 3 ffi 
 
RAILWAY SIGNALS 
 
 required position by means of another lever, after 
 which he locks them afresh by replacing the first lever. 
 
 The locking lever does its work through a small 
 appliance placed upon the line close to the points, 
 between the rails, called a facing-point lock. It is 
 very simple, but very strong and reliable. A rod 
 passes from each tongue of the points, both rods 
 terminating in flat portions which slide in a groove 
 in the apparatus. Each of these flat pieces has a 
 hole in it, and through this hole there can shoot a 
 bolt exactly similar to the bolt with which we fasten 
 our front doors. To be more correct, each of the 
 flat parts has two holes, so placed that when the 
 points are correctly set in one position the bolt 
 can shoot through one of them, and when in the other 
 position through the other. 
 
 Consequently, if anything should go wrong with 
 the points, so that they do not close properly, the 
 lock will not operate, for the bolt will not pass through 
 either of the holes. Now the bolt is connected by 
 rods to the locking lever in the signal cabin, so that 
 if it will not go through a hole the signalman finds 
 himself unable to work his lever and knows that 
 something is wrong. More than that, if he cannot 
 work his lever back into its right position, his signals 
 are locked. Thus we see that, in effect, he cannot 
 possibly lower his signals for a train to approach 
 the junction until the points are properly set and 
 locked. 
 
 It is interesting to notice, too, that the rod from 
 one tongue of the points is quite separate from 
 that from the other tongue, so that each is locked 
 
 169 
 
RAILWAY SIGNALS 
 
 separately. If either tongue is wrong, therefore, the 
 signals are locked at danger. 
 
 Indeed, the care of the railway authorities goes 
 even farther than this, for in many such cases 
 " detectors " are employed as well. It is just possible 
 that a long run of rod stretching from the signal 
 cabin to a distant junction might give in some way, 
 and so enable a signalman to move his lever without 
 actually locking the points, and it is this danger 
 which the detector guards against. 
 
 It consists of a small cast-iron box securely fixed 
 to the sleepers close to the points concerned. Through 
 it there pass in one direction two slides, connected 
 to the two tongues of the points. At right angles to 
 these there passes another slide. The single slide 
 crosses over the other two, but does not clear it, so 
 a notch is cut in it through which the edges of the 
 two slides pass. Thus, you see, the single slide 
 cannot move, because of the two slides fitting into 
 the notch. 
 
 There are, however, two notches in each of the two 
 slides, and these notches are made to correspond 
 with the two correct positions of the points. When, 
 therefore, the points are set correctly for either 
 route the single slide can move, but if the points or 
 either of them be the slightest distance out of a correct 
 position the single slide is held. 
 
 Now the wire which works the signal protecting 
 these points is made to pass through the single slide, 
 or rather the wire from the cabin is fastened to one 
 end of it and the wire to the signal is attached to 
 the other end ; in other words, the slide forms a 
 
 170 
 
RAILWAY SIGNALS 
 
 part of the connection between the cabin and the 
 signal, so that if the points be wrong, no matter 
 what may happen in the signal cabin, the signal 
 itself cannot be lowered. Thus every possibility of 
 failure is provided against. 
 
 The instrument shelf now demands our attention. 
 First and foremost, the " block telegraph " instru- 
 ments call for notice. If would, of course, be quite 
 possible for the signalmen to communicate to each 
 other the necessary information for the working of 
 the trains by ordinary telegraphy. It is safer, 
 however, to use special instruments. There are 
 several different varieties of these, but in essence 
 they are the same. There are, of course, always two, 
 one for the up direction and one for the down. 
 
 Each of them consists of a neat little cabinet with 
 a small glazed window, while at some convenient 
 spot there is placed a bell, that for the up instrument 
 being markedly different in tone from the other. 
 
 Normally, there shows through the window the 
 words " line blocked," while the operating handle 
 below the window hangs down vertically. 
 
 The signalman at the next cabin, by means of a 
 prearranged number of rings on the bell, announces 
 that he has a train coming along and asks for per- 
 mission to send it forward. Our signalman moves 
 the little handle over to one side and the ticket at 
 the window changes to " line clear," the instrument 
 in the next cabin thereupon doing the same. The 
 other man then lowers his signals, and presently a 
 signal on the bell indicates that it has passed him, 
 whereupon our man moves his handle to the other 
 
 171 
 
RAILWAY SIGNALS 
 
 side, the words " line clear " disappear from the 
 window and " train on line " takes their place. 
 
 Presently, when the train has passed, our man 
 places his handle vertically again, and the words 
 " line blocked " reappear. 
 
 This apparatus is very simple and therefore 
 reliable. Its particular virtue is that it sends only 
 three messages, the vital messages for maintaining 
 the safety of the trains, and each of these is not a 
 momentary signal, but remains on record until it 
 is cancelled by the next signal. There is no excuse 
 for a man thinking he has received the " line clear " 
 signal a minute ago and letting a train pass on the 
 strength of it. Unless the words are actually staring 
 him in the face at the moment, he knows that he 
 must not let the train go. 
 
 Another thing about it, and this aptly illustrates 
 what has been described as the third great principle 
 of railway signalling, is that any failure stops the 
 traffic rather than endangers the trains. The normal 
 signal " line blocked " is produced by the cessation 
 of the electric current. Battery failure or the 
 breakage of the wire would not, therefore, bring a 
 train into danger. 
 
 A third point about it, simple, yet in practice very 
 valuable, is that both instruments act in unison, so 
 that both the signalmen know what signal has been 
 sent and received, thereby making for a complete 
 understanding between the two. 
 
 Beside these instruments there are a number of 
 others with special functions. For example, signals 
 which cannot be seen easily from the cabin are 
 
 172 
 
RAILWAY SIGNALS 
 
 repeated by little models. There is a neat little box 
 with a glass front, and inside it a tiny signal, the arm 
 of which goes up and down in unison with the real 
 signal outside. 
 
 The acute observer may have noticed, while 
 waiting at a station, the apparatus upon the signal 
 for working these indicators. It consists of a little 
 round box fastened actually upon the signal arm 
 itself, and what may call attention to it is that a 
 loop of flexible wire hangs down, connecting this to 
 wires upon the post. Inside this little box there are 
 two insulated contacts a little distance apart, and 
 they are so placed that, when the arm is horizontal, 
 a little globule of mercury falls between them and 
 makes electrical connection. That enables current 
 from a battery to flow and keeps the indicator arm 
 raised also. As soon as the signal arm is lowered, 
 however, the mercury rolls away from the contacts, 
 cuts off the current and the indicator arm goes 
 down also. 
 
 Here again we notice two things : first, that by 
 putting the apparatus actually on the signal arm 
 itself several possible causes of failure are removed ; 
 and second, that failure of current will not delude the 
 signalman into thinking his signal is at danger when, 
 in fact, it is not. 
 
 Other indicators show whether the signal lights 
 are burning properly or not. These are worked by 
 the heat of the lamp expanding a metal bar and 
 thereby closing two contacts. If these be together, 
 current can flow from a battery and through an 
 indicator in the cabin which shows the words " light 
 
RAILWAY SIGNALS 
 
 in." If, however, the lamp should go out or 
 even burn badly the bar will cool, the contacts will 
 be drawn apart, the circuit broken and the indicator 
 will then proclaim " light out." 
 
 In addition to the mechanical and electrical 
 devices for making railways safe, there are rules 
 drawn up laying down certain methods which must 
 be rigidly adhered to, methods which may be said 
 to reinforce the purely mechanical or electrical 
 safeguards. 
 
 The devices so far described are such as may be 
 found in the great majority of signal cabins. There 
 are many others of a more or less special nature, in 
 use on busy lines or under special conditions. For 
 example, there are places where the signals are 
 worked by compressed air instead of by hand, others 
 where electricity is the moving force, others again 
 where points are worked by hand and signals by 
 electricity. 
 
 There are stretches, too, where the rails themselves 
 are made to do the signalling, which becomes auto- 
 matic. 
 
 There are several other electrical devices which 
 deserve mention, but these will all be found in other 
 chapters, as also will the special arrangements for 
 working single lines. 
 
 This chapter is intended to show the general 
 basis of all signalling, without which the later descrip- 
 tions might be hard to understand. 
 
CHAPTER XIII 
 AUTOMATIC SIGNALLING 
 
 ONE of the most fascinating things about the 
 modern railway is the way in which, on some 
 lines, the trains are made to be their own signal- 
 men ; or rather, to put it more accurately, each train 
 acts as the signalman in relation to the next one. 
 
 As a typical example of this we will take the 
 arrangements upon the Central London Railway, 
 the second, in point of time, of the " tube " railways ; 
 the one, in fact, in connection with which the name 
 " tube " came into use. The previous one, the City 
 and South London, was never called a tube, but 
 when the Central London was first opened there was 
 a universal fare of twopence for any distance, and 
 some wag hit upon the idea of calling it the " two- 
 penny tube " ; the name " caught on," and now the 
 word tube is the recognized term for all the low-level 
 underground lines. 
 
 Before going into details, however, it will be well 
 to explain the working of the " track circuit," which 
 is the basis of all modern automatic signalling. 
 There are one or two examples of automatic working 
 controlled by other means, but the track circuit 
 is so simple and so good that it is very unlikely that 
 
AUTOMATIC SIGNALLING 
 
 any more will ever be installed, except those based 
 upon it. 
 
 The track circuit as an invention is claimed by 
 both Great Britain and America. Away back in the 
 'seventies of last century the idea occurred to William 
 Robinson of Brooklyn and to W. R. Sykes of London, 
 and in all probability it was an original invention 
 in each case, neither knowing what the other was 
 doing. This simultaneous invention of the same 
 thing by two men quite independently of each other 
 is not at all an uncommon thing. Another feature 
 in which the track circuit resembles many other 
 inventions is that it was evidently before its time, 
 so that it was not until the 'nineties that it came to 
 be used to any extent. Now it is used more or less 
 on nearly every line. 
 
 The idea in itself is exceedingly simple. It is 
 based upon the fact that wood, even when wet, is a 
 very poor conductor of electricity, so that each rail 
 of a pair is fairly well insulated from the other. 
 
 Suppose, then, that you connect a small battery, 
 generating a force of a few volts, between the two 
 rails of a pair ; very little current, if any, will flow. 
 Then a train comes along with heavy metal wheels 
 and massive axles connecting them. These wheels 
 and axles form a path for the current from rail to 
 rail of very low resistance indeed, with the result 
 that a very considerable current will flow. 
 
 Now let us imagine that we want an indicator 
 which will warn us whenever a train is standing or 
 moving in a certain piece of line. We first isolate 
 that piece from the adjacent line by means of 
 
 176 
 
0) O 
 
 JS -(-> 
 
AUTOMATIC SIGNALLING 
 
 insulating bonds. These are specially shaped "fish- 
 plates " combined with insulating material, the effect 
 of which is to join the rails firmly to the adjacent 
 rails in a mechanical sense, yet to keep them quite 
 separate in an electrical sense. 
 
 Then we connect our battery to the two rails, 
 placing somewhere in the wire leading from the 
 battery to one rail a galvanometer, or other instru- 
 
 
 . i U*. 
 
 =3S iPg 
 t 
 
 t 
 
 I 
 
 I 
 
 1 
 
 U T. 
 
 ffl 
 
 ,- - |, | 
 
 { 
 
 Relay 
 
 Relay 
 
 Bettery 
 
 Fig. 12. DIAGRAM SHOWING HOW A TRACK CIRCUIT 
 
 WORKS IN ITS SIMPLEST FORM. 
 (Worked by steady current from a battery.) 
 
 I, I, I, are insulating joints in the rails. Arrows show course 
 of current. In the right-hand section the current has to pass 
 through and energize the relay. In the left-hand section the 
 pair of wheels form an easier path for the current, which is 
 thereby cut off from the relay. The relay controls the signal 
 or other apparatus. (Alternating current track circuits are 
 just the same in principle.) 
 
 ment which tells us when current is flowing. If we 
 watch the galvanometer as a train approaches this 
 insulated " section " of line we shall see the needle 
 suddenly swing over, indicating that the train has 
 entered the section. Later we shall see it swing 
 back, and then we shall know that it has passed out 
 at the other end of the section. But so long as the 
 section is occupied the needle will be held over by the 
 current. 
 
 M 177 
 
AUTOMATIC SIGNALLING 
 
 That would be a form of track circuit, but it would 
 suffer from a very serious fault so far as signalling 
 is concerned. The fault is this : the breakage of 
 one of the wires, or the failure of the battery would 
 give the same indication as the absence of a train. 
 Consequently, a train might be in the section while, 
 owing to one of these quite possible accidents, the 
 galvanometer would show the section clear. 
 
 Fortunately that difficulty can be overcome quite 
 easily. Let us connect the battery to the two rails 
 at one end of the section and the galvanometer to the 
 same rails at some other point. The current will 
 then flow along one rail, through the galvanometer 
 and back along the other rail, and so long as the 
 section is clear the galvanometer needle will be held 
 over. As soon as a train enters the section, however, 
 the wheels and axles will afford the current a much 
 easier path than that through the galvanometer, 
 with the result that nearly all of it will take that 
 path and very little indeed will pass through the 
 galvanometer, the needle of which will go to zero. 
 
 Under this arrangement the breakage of a wire 
 or the failure of a battery will give the same indica- 
 tion as the presence of a train in the section, so that 
 an error, if it occurs, makes for safety. 
 
 The principle of the track circuit, therefore, as 
 used, is that the train itself forms an easy path for 
 the current and thereby short circuits it, or in other 
 words, leads it away from the indicating instrument. 
 The latter is normally energized by the current 
 from the battery, and the train indicates its presence 
 by depriving it of the current. 
 
 178 
 
AUTOMATIC SIGNALLING 
 
 In practice very feeble currents are employed for 
 this work, far too feeble to work a signal, or, indeed, 
 anything heavier than a very delicate instrument, 
 hence the use of what is called a " relay." These 
 are instruments which are in themselves quite 
 robust, but which contain one very light moving 
 part very delicately poised. This the feeble currents 
 are able to move, and by moving complete or break 
 a second circuit through which can flow a powerful 
 current from a local source. Thus the feeble current 
 from the track circuit can be made to control a 
 second current of any power required, to work 
 signals or other apparatus. 
 
 On steam lines the use of track circuits is a very 
 simple matter, because the lines can be divided up 
 into sections, and the sections insulated from each 
 other without difficulty. On electrically driven 
 lines, however, the rails often form the return path 
 for the traction current, so that they cannot be 
 completely insulated from each other ; or even if 
 there be a fourth rail for the return of the traction 
 current some of the latter might by accident leak 
 on to one of the track rails and interfere with the 
 track circuits. The Central London will provide us 
 with an example of how this problem is simply and 
 satisfactorily dealt with. 
 
 When it was first built it was signalled on the 
 system known as " lock and block." Under this, 
 the line is divided up into " sections," and not more 
 than one train is allowed to be in a section at one 
 time. 
 
 To ensure this there is a signal box at the 
 
 179 
 
AUTOMATIC SIGNALLING 
 
 commencement of each section and a signal. All 
 the boxes are connected by telegraph wires and fitted 
 with certain special instruments. Let us take two 
 boxes, by way of illustration, and call them A 
 andB. 
 
 A train is approaching A, and the signalman, let 
 us suppose, tries to lower his signal to let it pass. 
 He finds that he cannot do so, for it is locked. He, 
 therefore, sends a message by wire to B box asking 
 the man there for permission to send the train on. 
 If all is clear, B sends back a message over the wires 
 in a certain prearranged way which has the effect of 
 unlocking the lever at A box. The A man then 
 lowers his signal and allows the train to proceed. 
 
 Suppose now that a second train quickly approaches 
 A, and A again asks B for permission to send it 
 forward. B cannot now send back the required 
 message because, after sending it for the previous 
 train, his instrument became locked until such time 
 as the first train should pass over a treadle under 
 the rail, and by so doing release it. Thus the second 
 train has to wait at A until the first train has passed 
 out of the section, and in doing so has unlocked the 
 instrument at B. Then, and only then, can the man 
 at B send the series of electrical currents necessary 
 to unlock A lever again. As a matter of fact, the 
 careful signalman would not attempt to make these 
 movements, but it has been put like that in order 
 to show that if by accident he should attempt to 
 do so he would be prevented by the apparatus. 
 
 Now it will be realized readily that to go through 
 this series of operations the exchanging of the 
 
 180 
 
AUTOMATIC SIGNALLING 
 
 necessary messages with the next box and the pulling 
 of the necessary levers takes an appreciable time. 
 
 It will also be readily understood that the number 
 of trains which a line can accommodate will depend 
 upon the length of the sections. By reducing the 
 length of the sections the trains can be brought 
 closer together and more of them got through in a 
 given time. But clearly, it is no use to make a 
 section so short that a train can pass from end to 
 end in less time than the signalling takes up. Such 
 a section would be a cause of delay rather than 
 the reverse, because trains would always be stopped 
 while the signalling operations were carried through. 
 
 This was the dilemma which faced the directors 
 of the Central London. They wanted to increase 
 the density of the traffic, in other words, to run the 
 trains closer together, yet the signalling system then 
 in vogue prevented it. Hence they were compelled 
 to adopt the automatic system which was already 
 doing so well on other underground lines in London. 
 
 The first thing to be done was to divide up the line 
 by insulating joints into suitable sections, electrically 
 insulated from each other, so that track circuits 
 could be installed. But, as already pointed out, the 
 rails are required to carry the return traction current. 
 It was therefore necessary to insert a device at each 
 joint whereby the traction current could " dodge 
 round " the insulating bond, while the track circuit 
 current would be stopped. At first sight this seems 
 impossible, but it is quite simple if you employ two 
 different kinds of current. 
 
 As explained in the chapter on electric traction, 
 
 181 
 
AUTOMATIC SIGNALLING 
 
 there are two sorts of electric currents. The elec- 
 tricity is just the same ; it is only the current which 
 varies. One of these flows straight on, always in 
 the same direction. The other " alternates," flowing 
 first in one direction, then in the other, generally, 
 in practice, making a complete set of changes fifty 
 times every second. The first sort of current, con- 
 tinuous or direct, flows through any coil of wire 
 
 Rail Rail 
 
 ARROWS SHOW COURSE OF 
 TRACTION CURRENT 
 
 J Rail || Rail ^ 
 
 Fig. 13. DIAGRAM SHOWING HOW THE IMPEDANCE BOND 
 
 IS ARRANGED. 
 
 It sorts out the two kinds of current, allowing the traction 
 current to pass but stopping the signal current. 
 
 I, I, Insulating joints. The impedance bonds consists of iron 
 cores, wound, as shown, with thick copper wire. Coils so 
 formed pass steady current with ease, but offer an almost 
 insuperable obstacle to alternating current. 
 
 quite readily. If, however, the coil be mounted 
 upon an iron core, it acquires a property called 
 " Impedance," which offers considerable obstruction 
 to the passage of an alternating current. 
 
 At every insulated joint, therefore, an " im- 
 pedance bond " has been placed, through which 
 the direct or continuous current from the motors 
 flows past the insulation, while the alternating 
 current for the track circuit operations is stopped. 
 
 182 
 
AUTOMATIC SIGNALLING 
 
 The " impedance bond " is quite simple in con- 
 struction, being merely a bar of copper bent round 
 into a coil, with a suitable iron core inside it, the 
 whole contained in an iron box fixed to the sleepers. 
 It is connected to the rails by flexible cables. It 
 needs little or no attention, but may safely be left 
 to do its duty. 
 
 But, someone may ask, is it not possible for the 
 traction current to get to the relay instead of the 
 track circuit current, and so give a false signal ? It 
 may get there, but it cannot give a false signal. 
 Just as the impedance coil can discriminate between 
 alternating and direct current, so can relays. In 
 this case a type of relay is used which will respond 
 to an alternating current, but will take absolutely 
 no notice of a direct current. 
 
 We are, however, getting on too fast. The line, 
 we will take it, has been divided up into convenient 
 sections, the divisions being in many cases the same 
 as before, but in other cases altered in order to reduce 
 the length of some of the sections and so expedite 
 the traffic. Except in a few cases the signal boxes 
 disappear entirely, as signal boxes at all events. 
 Instead of the levers in the signal boxes the track 
 circuits take control of the signals, in the following 
 simple manner. By entering a section, a train short 
 circuits a relay as already explained, and that puts 
 to danger a signal behind it. So long as the train 
 remains in the section that signal remains at danger, 
 but when it passes out of the section the signal goes 
 to " clear." 
 
 Unlike the ordinary line, where the signals are 
 
 183 
 
AUTOMATIC SIGNALLING 
 
 normally at danger, these signals are normally at 
 " clear," but each train as it goes puts the signal 
 immediately behind it to danger, thereby preventing 
 the next train from following too closely. The 
 second train, it will be noticed, can never enter a 
 section until the previous one has left it. Two trains 
 can never be in a section together. 
 
 To make assurance doubly sure, there is on the 
 ground near each signal an " automatic stop." This 
 is a mechanical device which works in conjunction 
 with the signal. When the signal goes to danger an 
 iron arm rises up and stands in the way of a pro- 
 jecting lever upon the trains. This lever is in effect 
 the handle of a cock, the opening of which puts on 
 the compressed air brake upon the train. Should a 
 train, therefore, overrun a signal this comes into 
 operation, the brake goes on and the train is quickly 
 brought to a standstill. When the signal is at " clear," 
 however, the arm lies down out of the way of the 
 lever on the train, so that the trains can run past it. 
 
 As a matter of fact, the insulating joints which 
 form the ends of the track circuits are not just 
 where the signals are, but are some distance farther 
 on. This distance, which is called the " overlap," 
 varies according to the gradient of the line at the 
 point, the idea being that it shall be long enough for 
 a train to pull up in. But for this arrangement a 
 train might stop just beyond a signal, and a second 
 train coming upon that signal unexpectedly might 
 be unable to pull up in time and so run into the one 
 in front. With the overlap, however, this can never 
 happen. 
 
 184 
 
AUTOMATIC SIGNALLING 
 
 The signals on this line are not movable, but 
 consist of two electric lights, one above the other, one 
 with a red lens and one with a green lens ; only one 
 
 Two Coils of wire 
 hown separate but 
 actually wound on 
 same Iron core 
 
 Supply Mains. -< 
 
 Fig. 14. DIAGRAM SHOWING HOW ONE RELAY CONTROLS 
 
 BOTH THE RED AND THE GREEN LAMP. 
 
 When the relay is caused by the track circuit to open, current 
 flows from the main at A through the red lamp. When the 
 relay closes, current flows from the main through the green 
 lamp. It also neutralizes the impedance in the coil so that the 
 red lamp becomes short-circuited. 
 
 is illuminated at a time. When the line is clear the 
 green one lights up, when it is otherwise the red one 
 shows. 
 
 185 
 
AUTOMATIC SIGNALLING 
 
 At first sight it seems as if this might be dangerous, 
 for we all know what tricks electric wires play at 
 times, and it seems possible that through a short 
 circuit the green might show when it ought to be red. 
 This possibility is provided against in a very ingenious 
 manner. 
 
 The current from the supply passes through the 
 relay to the green light and then through a small 
 coil. Current also passes from the supply to the red 
 light, but the line to the red light forks, the light 
 being in one branch and another small coil in the 
 other branch. The current to the red light circuit 
 is always on. 
 
 Let us assume that there is a train in the section, 
 in which case the relay is open and no current is 
 flowing to the green light. The current in the red 
 light circuit has two paths open to it, one through 
 the light and the other through the coil. But, as 
 we saw just now, a coil has the property called 
 " impedance," which obstructs the passage of alter- 
 nating current, which this current is. Therefore, the 
 path through the coil is almost blocked and practically 
 the whole of the current passes through the light, 
 which glows brightly. 
 
 But now let us suppose that the train has passed 
 out of the section. The relay closes the green circuit 
 and the green light shows. Of course, when the 
 current flows to the green light it also flows through 
 the small coil which is in the same circuit, and that 
 small coil is wound with the other small coil around 
 the same core. The effect of the green coil upon 
 the red coil is to reduce the impedance of the latter, 
 
 1 86 
 
AUTOMATIC SIGNALLING 
 
 with the result that current flows freely through it 
 and scarcely any through the red light, which there- 
 upon goes out. Thus the one relay controls both 
 circuits, and whatever happens a dangerous indica- 
 tion cannot be given. The two lights may under 
 certain conditions light up together, but under no 
 conditions can the green light show alone when it 
 ought to be red. The failure of an electric light bulb 
 is provided against by having two for each colour of 
 different ages. 
 
 Most of the signals are, of course, in tunnels, but 
 those which are in the open are (with one exception) 
 of the same type, a hood being placed over each so 
 that it can be seen clearly from a distance even in 
 broad daylight. 
 
 There are no distant signals on this line, but in 
 many cases, where an approaching driver does not 
 get an uninterrupted view of the signals, repeater 
 signals are used. These are just the same, except that 
 instead of being red and green they are yellow and green. 
 
 At one or two spots on the line there are cross- 
 overs or sidings, and at such points the old locking- 
 frame remains. These locking-frames are, however, 
 worked into the automatic system in a beautifully 
 simple manner. 
 
 The levers are still there and the rods for operating 
 the points, but the old signal has gone, its place 
 having been taken by an automatic signal. The 
 lever which used to work it has been fitted with an 
 electric switch, through which passes the current 
 from the track circuit. When this lever is pulled 
 the switch is closed and the signal is then controlled 
 
 187 
 
AUTOMATIC SIGNALLING 
 
 solely by the track circuit. When it is put back the 
 switch is thereby opened and the signal goes to 
 danger just as if it had been operated by a train. 
 
 Normally, then, the lever is left in the " pulled " 
 position, under which conditions the signal works 
 automatically, as if the lever did not exist, and the 
 point levers are securely locked. When it is put back, 
 however, it sets the signal to danger and also, 
 through the working of the ordinary inter-locking 
 mechanism, frees the point levers. During the 
 shunting the point levers themselves, as of old, lock 
 the signal lever and so keep the signal at danger, 
 but when the shunt is completed and the points 
 have been restored the signal lever can be pulled once 
 more and the automatic working is thereby restored. 
 
 At the two ends of the line there are small signal 
 boxes fitted up on the electro-pneumatic principle. 
 
 There is a supply of alternating current all along 
 the line for lighting and the current for the track 
 circuits is drawn from the same source, the correct 
 voltage being obtained by means of transformers, 
 small " induction coils " by which the voltage of 
 alternating current can be easily changed. 
 
 The points at the two terminal stations and the 
 train-stops are actuated by compressed air at 60 Ibs. 
 pressure carried in small iron pipes. 
 
 More recently a line has been constructed forming 
 a continuation of the Central London line as far as 
 Baling, and this provides us with further interesting 
 examples of signalling, inasmuch as parts of it are 
 " semi-automatic," and there is in use what is known 
 as the " three-position upper-quadrant " signal. 
 
 188 
 
AUTOMATIC SIGNALLING 
 
 Semi-automatic signalling differs from automatic 
 in that the signals are to some extent worked by a 
 signalman from a signal box, but his actions are 
 subject to restraint by track circuits, and under certain 
 conditions the signals go to danger automatically. 
 
 The term " upper quadrant " means that the 
 signal arm, instead of moving downwards through 
 the " lower quadrant " to indicate " clear," rises into 
 the " upper quadrant." In three-position signals 
 the arm rises from the horizontal, which as usual 
 
 (8)1 I (b)l i (c)| I (d)l I _ 
 
 (1) J (2) (3) ' (4) J/ ?) 
 
 I I I I 
 
 Fig. 15. DIAGRAM SHOWING THE OPERATION or THREE- 
 POSITION SIGNALS WORKED AUTOMATICALLY. 
 
 I = Insulating joints in rails. Direction of traffic left to right. 
 One train (denoted by the pair of wheels on right-hand side) 
 has just passed into section (5), consequently signal (d) is at 
 danger, signal (c) is at caution and signal (b) is at clear. 
 
 The second train, having just passed from section (1) into 
 section (2), has itself put signal (a) to danger. Signal (b) is 
 now clear, but will change to danger as soon as the train enters 
 section (3). At that moment, too, signal (a) will go to caution. 
 
 means " stop," to a mid position, which means 
 " proceed with caution," or to a vertical position, 
 which indicates " clear." 
 
 The use of the upper quadrant is convenient in 
 that it removes the necessity of balancing the arm 
 in order to make it go to danger of itself. It also 
 has the result that something falling upon it, such 
 as snow, cannot make it take up the " clear " position 
 when it ought not to do so. Further, when the three- 
 positions are used, the upper quadrant is almost 
 essential, because the interference of the post makes 
 
 189 
 
AUTOMATIC SIGNALLING 
 
 it practically impossible to obtain three clearly 
 discernible positions in the lower quadrant. 
 
 A three-position signal in the " caution " position 
 shows a yellow light, the lights for the other positions 
 being red and green as usual. 
 
 The signals in this case are not only controlled, 
 but actually moved by electricity, there being a 
 little motor on the post for that purpose. 
 
 Taking those parts of the line where the working 
 is automatic the three-position signals work in the 
 following manner. 
 
 A signal is at danger, a train having just entered 
 the section. As soon as it leaves the section the 
 arm goes up half-way. When it leaves the next 
 section it goes right up. The movements of the 
 signal, therefore, are controlled by the mutual 
 action of two track circuits, the first of which can 
 put the arm to the caution position, but both of 
 which are necessary to put it to the clear position. 
 
 In all cases the action of the signal arm is pro- 
 duced by current flowing from a relay to the motor 
 and causing it to wind up the signal arm, so to speak, 
 to the required position, where it is held by a magnet. 
 Any interruption of the current de-energizes the 
 magnet and permits the arm to fall back to danger. 
 
 The semi-automatic working is at junctions where 
 the intervention of a human intelligence is absolutely 
 necessary. What it amounts to is that the signalman 
 can put to danger signals which the track circuits 
 would leave at " clear," in order to manipulate 
 points. The track circuits, however, remain on 
 guard, as it were, preventing the man from putting 
 signals to " clear " when it is not safe to do so. 
 
 190 
 
AUTOMATIC SIGNALLING 
 
 Signals which are automatic are, on this line, 
 distinguished from those which are under human 
 supervision by having pointed ends instead of the 
 usual square ends. The reason for this is interesting. 
 If an ordinary signal goes out of order and stops a 
 train when it need not do so, the signalman can take 
 steps to remedy the defect at once, or can signal the 
 train forward by hand. If, however, an automatic 
 signal did the same thing it might be that no one in 
 the signal department knew about it for some con- 
 siderable time, during which a train might be standing 
 needlessly at it. The rule is, therefore, that after a 
 train has come to a standstill and stood still for one 
 minute it may move on past an automatic signal, 
 but it must move cautiously, being prepared to stop 
 short of any obstruction which it might find ahead. 
 
 On some lines, it may be remarked here, the 
 automatic signals are indicated by a black line 
 running lengthwise of the arm. 
 
 Where signal levers are used it is so arranged that 
 the signalman can at first only move his lever a 
 part of the way. This sets going the signalling or 
 point-moving operation which he desires, and when 
 that is complete a return indication frees his lever, 
 so that he can complete the movement. It is this 
 last little part of the movement which operates the 
 interlocking mechanism, so that other levers are not 
 unlocked until not only has the first lever been 
 moved, but the distant apparatus has actually re- 
 sponded to the movement. 
 
 It is difficult to see how any safety device could be 
 more complete. 
 
 191 
 
CHAPTER XIV 
 
 THE SIGNALLING OF A LARGE 
 TERMINUS 
 
 IN a previous chapter there has been described 
 the simple general principles of signalling, and 
 what has been said there will enable anyone to 
 understand the operation of the signals which afford 
 so much interest during a wait at a small wayside 
 station. This chapter deals with a very up-to-date 
 system of power signalling at the Central Station, 
 Glasgow, in its way one of the wonders of the world. 
 
 The term " power signalling " means that the 
 points and signals are not moved by the muscles of 
 the signalman, but by some form of power, the 
 signalman only opening or closing certain cocks or 
 switches which control the power. 
 
 In this particular case the power is electro-pneu- 
 matic, the actual movements being made by com- 
 pressed air, the valves of the compressed-air motors 
 being operated by electric currents, which in turn 
 are controlled by switches in the signal cabin. 
 
 In every signal cabin the levers are placed in a 
 long row, mounted in framing which forms guides 
 and supports for them, while close by, usually beneath, 
 is the interlocking apparatus, the whole thing being 
 
 192 
 
SIGNALLING OF A LARGE TERMINUS 
 
 called an " interlocking frame." The same general 
 form is retained even when the long levers of the 
 hand-worked apparatus give place to the small 
 switches of the electro-pneumatic. Thus, in this 
 great cabin, we have a frame of 374 levers, all mounted 
 in one row, with the interlocking apparatus just 
 beneath. The levers, while in general form similar 
 to the large ones, are quite small and the power 
 required to move them is very little. Thus, a man 
 can look after a much larger number of levers than 
 he could do if he had to work them by his own 
 power, and the staff of men required is thereby 
 reduced. 
 
 Further, it is possible when using power to work 
 points situated much farther from the cabin than is 
 practicable with human muscles with the result that, 
 as in this case, the whole working of a vast station 
 can be controlled from one cabin. 
 
 There is yet another point which, in a case like this, 
 is very important. The number of lines with the 
 necessary points, crossings and signals is so great 
 that the rods and wires necessary to work them by 
 hand would monopolize room on the ground which 
 cannot be spared. The pipes and electric wires 
 needed for the electro-pneumatic scheme can be 
 bunched together and stowed away in places which 
 would be quite impossible with rods and wires that 
 had to be movable. 
 
 The particular system used here is the Westing- 
 house, a system which originated in the United 
 States, but which has been adopted in Great Britain, 
 although to some extent modified in order to adapt 
 
 N I 93 
 
SIGNALLING OF A LARGE TERMINUS 
 
 it more effectively to the conditions which prevail 
 here. 
 
 Each little lever is interlocked with its fellows in a 
 manner very similar to that described previously and 
 the motion of a lever makes or breaks certain 
 electrical contacts, sending or stopping currents 
 which flow to the various " motors," upon the signals 
 or on the ground near the points. 
 
 The motors are cylinders of cast iron with a piston 
 inside each, and a piston rod very like that of a 
 steam engine. Pipes run to all the motors carrying 
 compressed air at a pressure of about 70 Ibs. per 
 square inch. 
 
 The valves which permit the compressed air to 
 enter the motors are worked by an electro-magnet, 
 which is energized by the current from the cabin ; 
 so that a current on flowing gives strength to the 
 magnet, thereby opening the valve and permitting 
 the compressed air to move the piston, the rod of 
 which communicates its movement to the points or 
 other mechanism. 
 
 The signal cabin which we are now considering is 
 a two-story structure about 107 ft. long and 16 ft. 
 wide. The upper floor, the signal box proper, has 
 glass windows practically all round, so that the 
 signalmen have an uninterrupted view in all directions, 
 and in addition there are four projecting bay windows 
 from which the men can get a better view lengthwise 
 of the cabin. It is on this upper floor, of course, 
 that the frame is placed. 
 
 All the signal posts in this installation are iron, 
 and many of them are arranged upon bridges which 
 
 194 
 
SIGNALLING OF A LARGE TERMINUS 
 
 span the line from side to side. There are fifteen of 
 these bridges, one, at least, of which is well over 
 100 ft. long. 
 
 There are, to the observer, strangely few signals 
 for so busy a station, the reason being a very in- 
 teresting one. 
 
 Suppose that from one line it is possible to enter 
 three platforms. There would be, under the ordinary 
 arrangement, three signals. In this case there is 
 only one, but in addition to that one there is an 
 indicator showing the words " To Platform " and a 
 large number. Thus, whatever platform the train 
 may be intended to enter is indicated by the number, 
 and the one signal arm suffices for all three. 
 
 The great advantage of this arrangement is that 
 by reducing the number of arms very considerably 
 it simplifies the work of the drivers. Instead of 
 having to pick one arm out of a number and to 
 count upwards or downwards to see which platform 
 it relates to, he has only the one arm and the in- 
 dicator, which he reads instantly and without effort. 
 
 The same principle is applied for trains coming 
 out of the station. In that case there are several 
 ways from each platform on to different roads, so 
 that for each platform there is one signal and below 
 it an indicator with the words " To Line " and a 
 number. 
 
 The indicators consist of a case with slides in it, 
 each slide having a different number upon it. The 
 slides normally reside in the upper part of the case, 
 behind the words " To Platform," or " To Line," as 
 the case may be. The case also contains a shutter, 
 
 195 
 
SIGNALLING OF A LARGE TERMINUS 
 
 which is normally down and remains down so long 
 as the signal is at " danger." 
 
 It must not be thought that there is only one lever 
 because there is only one arm. There are, in fact, 
 the same number of levers as there would be arms 
 under the ordinary conditions. On one of these 
 being pulled, it sends a current to the signal which 
 operates an electric lock and so releases one of the 
 slides. This current also starts a motor, which lowers 
 the correct slide into position behind the shutter. 
 When the slide has descended to its correct position 
 it closes an electric contact, which sets another 
 motor going and this motor lowers the signal arm 
 and raises the shutter. 
 
 It often happens in a terminus such as this that a 
 train is at a platform where it is desired to put a 
 second train. If, under such conditions, the ordinary 
 signal were used the driver would probably think 
 that the platform was clear and he would go in 
 prepared to stop at the farther end, with the result 
 that he would be quite likely to crash into the train 
 already there. To meet this difficulty there is, under 
 the other arm, a smaller one called a " calling-on " 
 arm, the purpose of which is to tell the man to move 
 forward, but to go slowly and carefully so that he 
 can stop short of any obstruction which he may 
 encounter. This arm is worked in just the same way 
 as the other, but by a separate lever. 
 
 At several points in the area controlled from the 
 signal box there are points for shunting which it is 
 not convenient to work from the box itself. These 
 are, therefore, worked by the shunters themselves 
 
 196 
 
SIGNALLING OF A LARGE TERMINUS 
 
 by means of " ground-frames," by which is meant 
 levers mounted in small frames upon the ground. 
 At first sight this seems a very dangerous thing to 
 do, to allow shunters out of doors to interfere with 
 the points, but all danger is provided against in a 
 perfectly satisfactory manner. When he wishes to 
 " make a shunt " the shunter pulls over one lever 
 half-way. He can do no more than this, for the 
 moment. 
 
 If the signalman knows that all is right and that 
 the shunting may safely take place, he, too, pulls 
 over a lever in the cabin, which action causes a 
 current to flow and to unlock the levers in the ground- 
 frame. The shunter can then complete the move- 
 ment of his lever and proceed with the shunting. But 
 that is not the whole story ; the completion of its 
 movement by the lever in the ground-frame " back- 
 locks " certain levers in the cabin, in other words, 
 locks them so that they cannot be moved until the 
 shunting is complete, when, by a similar series of 
 movements, the ground-frame is locked once more 
 and the levers in the cabin freed. 
 
 Certain parts of the lines are protected by means of 
 " track circuits," which have already been explained 
 in detail under the heading of " automatic signall- 
 ing." It is sufficient here to remind the reader that 
 the effect of a track circuit is to cut off a current 
 of electricity which normally flows to the signal box 
 as soon as a vehicle of any sort enters the piece of 
 line which the track circuit is to protect. For example, 
 take the case mentioned just now, where a train is 
 standing at the remote end of a platform. It would 
 
 197 
 
SIGNALLING OF A LARGE TERMINUS 
 
 be possible for a signalman to forget that it was 
 there and to lower the signal to allow a second train 
 to enter. If, however, the line alongside the platform 
 be track circuited the train standing there cuts off 
 current from the signal box and so causes the corre- 
 sponding signal to be locked, so that the signalman 
 cannot lower it. 
 
 The track circuits are also made to actuate 
 illuminated diagrams in the signal box. These are 
 diagrams of the lines over which the signalman has 
 control, divided up into sections, behind each of 
 which is a small electric light. When a section is 
 free the lamp behind it lights up, but as soon as a 
 vehicle of any sort enters it, and so long as it remains 
 there, the light goes out. Thus, by a glance at the 
 diagram, the signalman can see which sections are 
 clear and which occupied. There are two of these 
 diagrams in the signal cabin under consideration. 
 
 In a previous chapter on signalling the locking of 
 facing points was described, and it will be remembered 
 that two levers were required, one to lock and unlock 
 and the other to set the points. In the electro, 
 pneumatic system installed at Glasgow Central the 
 pneumatic motor is made to perform both operations 
 together in a beautifully simple manner. The air 
 enters and the piston commences to move ; the first 
 2 ins. or so of movement is employed in drawing 
 back the bolt and so unlocking the points, the next 
 part of the stroke moves the points over and the 
 third part re-locks them in their new position. 
 
 In addition to this, the signalman is not able, at 
 first, to put his lever right over. He finds it physically 
 
 198 
 
SIGNALLING OF A LARGE TERMINUS 
 
 impossible to do so ; it simply will not go right over. 
 He has to wait until the motor has done its work ; 
 then, and then only, does it send back to the box a 
 " return indication," which permits the man to 
 complete the movement of his lever. And, of course, 
 it is only when the movement is completed that the 
 signals are unlocked so that he can let a train through 
 to the points. Assurance is thus made doubly sure 
 that no train can approach facing points until they 
 have been correctly set and locked. 
 
 Another feature of this system is known as " con- 
 stant detection." Should anything happen to derange 
 the points after they have been set, the signal is 
 automatically put to danger, or if it is already at 
 danger is locked in that position. 
 
 The compressed air is obtained from an electrically 
 driven compressor, with a steam-driven one as 
 " stand-by " in case of accident. The electric current 
 :s obtained from storage batteries periodically charged 
 up by means of suitable machinery installed for the 
 purpose. . 
 
 Thus we see how the modern railway provides for 
 the safety of its passengers, but it would be unfair 
 not to mention how it cares, too, for its employes. 
 The signal box of which we have been speaking is 
 fitted up with every convenience for making the 
 lives of the signalmen as comfortable as possible 
 while they are at work. 
 
 One ought not to forget, too, the men themselves 
 who have to work and to maintain this wonderful 
 signalling machine. To work it needs a clear brain, 
 well trained by long experience. True, it is so 
 
 199 
 
SIGNALLING OF A LARGE TERMINUS 
 
 arranged that a novice even could hardly cause an 
 accident, but he would never get any trains in or 
 out. To stand for a few moments in a signal box 
 like this is impossible without a strong feeling of 
 admiration for the clear-headed, reliable men upon 
 whom the safety and celerity of the train service 
 so largely depends. 
 
 200 
 
CHAPTER XV 
 RAILWAYS IN FOGGY WEATHER 
 
 IT is a mistake to assume that fog is the result 
 of damp only. The water-vapour often present 
 in air cannot condense into those fine drops 
 which constitute fog unless there be present a 
 quantity of dust or other solid particles around 
 which the droplets can form. Unfortunately, particles 
 of soot serve this purpose exceedingly well, with the 
 result that the smoke which arises from the in- 
 numerable chimneys of a populous town assists 
 materially in producing fog and also makes such fog 
 peculiarly dirty and opaque. 
 
 Hence, just at those spots where railway traffic is 
 likely to be most congested, dense and frequent 
 fogs are likely to occur. This is particularly dis- 
 concerting to the railway manager, for it brings 
 to nought many of his most carefully planned schemes 
 for the safe and quick working of the trains. 
 
 Since a driver cannot see, or, at all events, can only 
 see faintly, in foggy weather, audible signals have to 
 be given to him in place of the usual visible ones, 
 from which fact arises the use of the well-known 
 fog signal. 
 
 This is a little tin box, not unlike those tin boxes 
 which are made to contain vaseline, boot polish and 
 
 201 
 
RAILWAYS IN FOGGY WEATHER 
 
 similar pasty substances. Inside it are three little 
 iron pegs which stand in an upright position with a 
 percussion cap on the top of each. In addition there 
 are a few grains of gunpowder, while to the bottom 
 of the case is soldered a short strip of thin, flexible 
 metal by which the " detonator," to give it its official 
 title, can be clipped upon the rail. 
 
 As soon as a fog comes on, a number of employe's 
 of the line, mostly platelayers, repair to certain 
 appointed places where they report to a stationmaster 
 or other official. This official assigns to each man a 
 special position, generally at the foot of a certain 
 signal post, and issues to him a supply of detonators. 
 The man, having reached his post, finding a signal 
 at danger, places a detonator on the line and leaves 
 it there so long as the signal is up. If the signal falls 
 he takes up the detonator. If a train comes along 
 and explodes the detonator he calls to the driver 
 when the signal has fallen that he may proceed. 
 As soon as it has gone and the signal has been restored 
 to the danger position he puts a new detonator down. 
 
 The practice varies somewhat, but in many 
 places two are put down instead of one to guard 
 against the possibility of failure. 
 
 Where there is only one arm on a post and no other 
 posts near, the " fogman," as he is called, only has 
 one line to look after, but if there be several signals 
 on the same post or near together, he may have to 
 look after several. 
 
 In case the fog should last a long time there is 
 usually provided a rough shelter of some sort for 
 the man, and the means of making and keeping up 
 
 202 
 
RAILWAYS IN FOGGY WEATHER 
 
 a fire. On a foggy night the fogman's hut and fire 
 frequently look to the passing traveller very cosy 
 and comfortable, but the writer can assert from 
 practical experience of somewhat similar conditions 
 that the comfort is chiefly apparent. 
 
 Of recent years much has been done to improve 
 
 DETONATOR 
 
 Fig. 16. DIAGRAM SHOWING HOW THE "FOGGING MACHINE" 
 WORKS. 
 
 In position (1) the arm is holding the detonator on the line. 
 
 In position (2) the detonator is being held clear of the line, 
 the signal being at "line clear." 
 
 In position (3) the arm has swung right back to pick out a 
 fresh detonator from the magazine. 
 
 The spent detonator is dropped as the arm swings back 
 between position (2) and (3). 
 
 upon this rather primitive method of fog signalling, 
 at all events in busy places. 
 
 For one thing, there is a machine actually connected 
 to the signal mechanism, so that an arm shoots for- 
 ward and holds a detonator upon the line so long as 
 the signal is up, but withdraws it when the signal 
 
 203 
 
RAILWAYS IN FOGGY WEATHER 
 
 falls. Or to be more precise, it holds two detonators 
 and not simply one. It is not quite automatic, 
 however, because when the detonators have been 
 exploded a man has to place others in the clips at 
 the ends of the arms. 
 
 Another interesting little contrivance may be 
 mentioned in this connection, although its purpose 
 is not to help the men, but to save detonators. It 
 consists of a little arm with a clip at the end capable 
 of holding a detonator. This arm is fixed at one 
 end of a rod a few feet long, to the other end of 
 which is attached a strip of thin sheet iron. The 
 sheet iron is placed close to the spot where a detonator 
 is fixed upon the rail, while the little arm holds 
 another detonator on the same rail a few feet further 
 on. If the first detonator goes off the explosion 
 blows against the piece of sheet iron, causes the rod 
 to turn and so lifts the second detonator clear of the 
 rail. Thus, if the first fails to go off the second 
 detonator comes into operation, but if the first does 
 its duty the second is not wasted. 
 
 Generally speaking the fogman assures himself of 
 the state of the signal by watching the movement 
 of the balance- weight near the foot of the post. He 
 may, of course, if the fog is not very bad, be able to 
 see the arm, or he may even, in exceptional cases, 
 have to climb the post. 
 
 In busy places Clayton's fogging machine is used, 
 in conjunction with little " fogging " arms low 
 down on the post. The fogging arms are very small 
 compared with those above, but they are large 
 enough for the purpose and, being mechanically 
 
 204 
 
RAILWAYS IN FOGGY WEATHER 
 
 connected to the larger ones, they form perfectly 
 reliable indicators, enabling the fogman to tell 
 easily and with certainty what the invisible arms at 
 the top of the post are doing. 
 
 On large posts with a number of arms, such as we 
 often see near large stations, there will be a similar 
 number of fogging arms, and close by there will 
 generally be seen a small frame, with a number of 
 little hand levers, like those in the signal box, only 
 smaller. There will be one lever for each fogging 
 arm, or, in other words, for each signal on the post. 
 
 From these levers rods run in various directions 
 to the " fogging machines," each of which is close 
 to the line upon which it operates. 
 
 Normally the machine shuts up into a small 
 compass and is covered with a light iron cover to 
 protect it from the weather, but when required 
 the cover is removed, the mechanism opened out, 
 and all is ready for work in a few seconds. 
 
 The essential part of the machine is a cleverly 
 contrived arm and hand. The hand has two fingers, 
 or a finger and thumb, with which it can grasp a 
 little metal tab upon the detonator. By this means, 
 in one of its positions, it holds the detonator upon 
 the line, so that a passing engine or vehicle would 
 explode it. 
 
 Now suppose the signal is lowered. The fogman 
 sees the corresponding fogging arm move, so he 
 places his hand upon the corresponding lever and 
 moves it into its middle position ; perhaps it should 
 have been explained that each of these levers can 
 be placed in three positions. 
 
 205 
 
RAILWAYS IN FOGGY WEATHER 
 
 The lever being in the middle position, the arm 
 also swings into its middle position, under which 
 conditions the detonator is held clear of the line. 
 As soon as the signal goes to danger again the man 
 replaces the arm in the first position, and the 
 detonator is held over the rail once more. 
 
 Let us suppose, now, that a train passes over the 
 detonator and explodes it. What is to be done 
 then ? The man simply pulls his lever into the third 
 position, by doing which he causes the arm to swing 
 round to where the reservoir is containing the supply 
 of detonators. 
 
 This reservoir is a small, square, vertical column, 
 very like that part of an " automatic machine " 
 which holds the packets of sweets. In it the deto- 
 nators are packed, one above another, there being 
 a space through which the bottom one can be readily 
 drawn out, and every time one is taken the whole 
 pile drop down, so that a new one takes its place. 
 
 The beauty of the thing, judged as a piece of 
 mechanism, is that as the arm swings back the 
 hand opens and drops the spent detonator, after 
 which it clips firmly hold of a new one. The lever 
 can then be moved back to either the first or the 
 middle position as required, carrying the new 
 detonator with it, all ready to do its work. 
 
 It is easy to see the advantages of this mechanical 
 method of handling fog signals. It enables one man 
 to do the fog signalling on a considerable number 
 of lines, and it enables him to do it, moreover, 
 without the danger of having to grope about crossing 
 the lines in, perhaps, worse than pitch darkness. 
 
 206 
 
RAILWAYS IN FOGGY WEATHER 
 
 The consideration of the arrangements for fog 
 signalling naturally lead to the question, " Why is 
 there not some way of indicating to the driver upon 
 his engine, if the signals are against him or not ? " 
 The device of letting off fireworks under the engine 
 certainly seems crude, and it may be that it is in 
 process of being done away. At all events, there 
 have been many suggestions for " cab signals," that 
 is, definite signals of some sort in the cab, which 
 would make a driver independent of fog signals of 
 the usual type. Of these various suggestions we will 
 notice first the one associated with the name of 
 Sykes, a name well known as that of one of the 
 pioneers in the use of electricity for railway signalling. 
 The following is a description of the " Sykes audible 
 cab signal." 
 
 It consists of two parts, one upon the line, 
 called the " ramp " and the other upon the 
 engine. 
 
 The term " ramp " means, in engineering language, 
 an incline, and in this case it indicates a length of 
 T-iron which is placed with the stem of the T upwards 
 on the ground between the rails. It is bent slightly 
 towards the middle, so that it slopes slightly upwards 
 from either end and then falls away again. It is 
 firmly fixed in specially designed chairs, which are 
 in turn secured to the sleepers. Moreover, for a 
 reason which will be apparent presently, it is 
 electrically insulated. 
 
 The apparatus beneath the engine, which is spoken 
 of as the " under-gear," appears to be a wrought- 
 iron box, from the bottom of which there projects 
 
 207 
 
RAILWAYS IN FOGGY WEATHER 
 
 a strong iron slide with a shoe made of specially 
 hardened iron at its lower extremity. 
 
 This shoe is also insulated electrically, from which 
 it will be gathered that it has an electrical function 
 of some sort, but for the moment we will consider 
 its purely mechanical purpose. This is to slide up 
 the ramp as the engine passes over it. 
 
 Striking the ramp near its lowest point it is raised 
 as the ramp rises, until, having passed the highest 
 point the ramp permits it to fall again. 
 
 If, then, one of these ramps be placed near to each 
 signal, the shoe upon a passing engine will inevitably 
 be raised as it goes by. The raising of the shoe will 
 lift the slide and the motion of the slide can be made 
 to do certain things. 
 
 Let us now imagine the cover to be lifted off the 
 " box " from which the slide projects. There we 
 see a number of small rods and levers, two little 
 cylinders and an electro-magnet. 
 
 One cylinder is connected by a pipe to the " train 
 pipe," which supplies the brakes throughout the 
 train with compressed air. This air, acting upon a 
 piston in the cylinder is always pressing one of the 
 levers in a certain direction, but the lever cannot 
 move because of a " trigger-like " arrangement 
 designed to prevent it. 
 
 When the plunger rises, however, it " pulls the 
 trigger," so to speak, releases the lever and allows the 
 compressed air to push it forward. That, in turn, 
 allows the compressed air to escape, with the result 
 that the brake is applied throughout the train. 
 
 Thus, when the shoe passes over a ramp it is 
 
 208 
 
rt 
 
 *t 
 
 -o ^ 
 
 1 1 
 
RAILWAYS IN FOGGY WEATHER 
 
 raised, that operates the plunger, which releases 
 the trigger, liberates the compressed air and puts 
 on the continuous brake. 
 
 All the apparatus for this, be it noted, is very 
 robust and strong, its action is very simple, it is 
 inconceivable that it could get out of order, and so 
 can be safely relied upon to give warning of danger. 
 
 The air, the escape of which puts on the brakes, 
 is led away through a pipe to a whistle on the cab, 
 so that in the event of his overrunning a signal a 
 driver not only finds his brakes go on, but also 
 hears a shrill whistle close to his ear. 
 
 All that happens, if the signal is at danger. When 
 it is at " line clear " events take a different course, 
 due to the action of a feeble electric current. 
 
 There is a wire running from the signal cabin to 
 the " ramp." There is also a switch attached to 
 the lever in the cabin, so arranged that when the 
 lever is normal the switch is open, but when it is 
 reversed (to lower the signal) the switch is closed. 
 The switch is only closed, then, when the line is 
 clear. The closing of this switch connects a battery, 
 through the wire, to the ramp. 
 
 Under these conditions the slide is raised as before 
 and the trigger is released, but the electric current, 
 passing from the ramp to the shoe, flows up into 
 the box and energizes the electro-magnet. This 
 magnet, when energized, prevents the lever, although 
 released by the trigger, from moving. The trigger, 
 therefore, falls back again into its normal state, 
 nothing having happened. 
 
 Thus, whereas the passage of an engine over a 
 o 209 
 
RAILWAYS IN FOGGY WEATHER 
 
 " dead " ramp stops the train, passage over an 
 "energized" ramp has no effect at all, for the 
 mechanical effect of raising the slide is neutralized 
 by the action of the electric current in energizing 
 the magnet. 
 
 Just, however, to let the driver know that he has 
 passed a signal at safety, the current, after passing 
 the electro -magnet, is led to an electric bell in the 
 cab. 
 
 The total effect is, then, that if a driver on a line 
 fitted with this apparatus were to go on with his 
 eyes shut, on passing a signal at " line clear " he 
 would hear a short ring upon the electric bell. When, 
 however, he came to one at danger the whistle would 
 sound and the brakes would go on. 
 
 But there is still one feature to be explained, 
 namely, the second of the two cylinders mentioned. 
 It also is connected to a pipe which leads to a valve 
 in the cab, to which valve is attached a handle, 
 called the " re-setting handle." When the apparatus 
 has applied the brakes, it is necessary to release 
 them again before the train can proceed, and this 
 can be accomplished by the simple movement of 
 the " re-setting handle." Its action permits com- 
 pressed air to enter this second cylinder, where, 
 by acting upon a piston, it pushes the whole con- 
 trivance of rods and levers back into its normal 
 state, re-sets the trigger and leaves it all ready for 
 action the next time it is required. 
 
 In this, as in so many other signalling devices, 
 we see how the electric current, uncertain though it 
 may be, is used with safety. There are so many 
 
 210 
 
RAILWAYS IN FOGGY WEATHER 
 
 little things which may upset the action of an electric 
 current that it is never relied upon to give a warning 
 of danger. A little dirt on some contacts, a slightly 
 run-down battery, a little chafing of the insulation 
 on a wire, a wire breaking, many little things may 
 possibly cause an electric current to fail. The result 
 is not serious, however, if things be so arranged that 
 failure indicates danger, as is done in the case just 
 considered. 
 
 The first idea was that the cab signal apparatus 
 should be applied to distant signals only, but there 
 is no strong reason why it should not be applied to 
 all signals if that should turn out to be desirable, 
 and for that the makers have made provision. 
 
 It will be remembered that at a distant signal a 
 train does not stop ; it only slows down in order to 
 be ready to stop, if need be, at the home signal. 
 Hence the need for a quick use of the " re-setting 
 handle." 
 
 But if it were used at home signals as well as at 
 distant signals a driver might " re-set " and go on 
 past a home signal. To prevent that, it is arranged 
 to make the ramp slightly higher at a home signal, 
 and the extra lift of the slide so alters the arrange- 
 ments inside the box that they cannot be re-set by 
 the re-setting handle. Under those conditions the 
 driver has to get off his engine and re-set from the 
 ground, thus compelling him to stop his train dead. 
 
 Of course, this apparatus would work just the 
 same in fine w r eather as in fog, and its advantages 
 would be by no means small as a safeguard against 
 a momentary lapse upon the part of a driver even 
 
 211 
 
RAILWAYS IN FOGGY WEATHER 
 
 in the finest weather : the historic accident at 
 Slough, for example, occurred upon a beautiful 
 summer afternoon, but it would have been quite 
 impossible had this apparatus been installed. As 
 a matter of fact, it was not even invented then. 
 
 Still, the chief benefits of the cab signals will no 
 doubt accrue when the weather is foggy. 
 
 A system very similar to this in its general features 
 has been in use on parts of the Great Western Railway 
 for a considerable time. It has a contact shoe on 
 the engine and a ramp between the rails, just like 
 the arrangement described above. It also sounds a 
 whistle and applies the brake in case of danger, 
 and rings a bell in the event of the indication being 
 " clear." The difference between the two systems 
 is in details. 
 
 In both these arrangements, it will be noticed, 
 the driver has to rely upon some other source of 
 information to let him know when the time comes 
 to proceed after having been stopped. He has to 
 find this out as best he can from the visible signal. 
 
 In the " Raven " system, used on the North- 
 Eastern Railway, even this difficulty is removed. 
 In this case the engine passes over a series of as 
 many as five ramps, one after another. 
 
 In the driver's cab there is a small model signal 
 arm enclosed in a glass case. The signals are conveyed 
 to the driver by these, but in order that he may be 
 saved the necessity of continually watching this 
 indicator a bell is employed as well. 
 
 The first ramp is placed about 150 yards before 
 the train reaches a distant signal. That one always 
 
 212 
 
[RAILWAYS IN FOGGY WEATHER 
 
 causes the bell to ring and the small arm to go to 
 danger. If, on reaching the distant signal, all the 
 signals are " off " for the train to proceed into the 
 next section, the arm falls and the bell ceases to 
 ring. This, of course, is due to the action of the 
 second ramp, which is near the distant signal. If, 
 however, the home signal is still " on " or at danger, 
 when the train reaches the distant signal, the arm 
 remains up and the bell continues to ring. The 
 driver, therefore, proceeds cautiously, passing over 
 a third ramp, during which the bell ceases for a 
 moment (the arm still remaining at danger) until 
 he reaches the fourth ramp, when, if the indications 
 are still against him, he stops. The cessation of the 
 bell signals while passing over a ramp are intended 
 to tell him just where he is, and to enable him to 
 stop exactly over the fourth ramp, thereby keeping 
 him in touch with the signalman. 
 
 The signalman can thus give him the order to 
 proceed at any moment, the indication to the driver 
 being the falling of the little signal arm and the 
 complete cessation of the bell. Or he can give him 
 the " calling-on " indication, whereby he is instructed 
 to draw ahead slowly as far as the starting signal. 
 The signalman gives this instruction by working a 
 switch in his cabin, which causes the small arm on the 
 engine to go up and down several times. 
 
 If he is thus " called-on " the driver proceeds as 
 far as the fifth ramp, over which he brings his engine 
 to a stand and from which he gets his final signal 
 to proceed. 
 
 The simple apparatus, employed in connection 
 
 213 
 
RAILWAYS IN FOGGY WEATHER 
 
 with the automatic signals on the London Under- 
 ground and elsewhere, is described in another chapter, 
 and there is a further device of a very simple character 
 employed on some of the open parts of the " Under- 
 ground " lines to assist the drivers in case of fog. 
 This consists of a powerful pair of electric lights, 
 one red and one green, placed by the side of the 
 line. When either of these lamps is " alight " it 
 causes a coloured glow in the fog, which can be 
 seen by a driver quite a considerable distance away. 
 
 214 
 
CHAPTER XVI 
 TRAFFIC CONTROL 
 
 IT frequently happens that a train on a branch 
 line has to wait near the junction, while trains 
 are running through on the main line, and in 
 such cases the branch passengers usually grumble 
 and complain. 
 
 As a matter of fact, if they would but consider the 
 difficulties of managing the vast traffic of a busy 
 line they would be surprised, not that there is delay 
 to a train, but that the trains ever got through at all. 
 
 When you come to think of the way in which the 
 trains pass through a busy junction first one way, 
 then another, first along one line and then along 
 another, it is astounding that they interfere with 
 each other so little. 
 
 As far as passenger traffic is concerned control 
 takes the form of working as closely as possible to a 
 prearranged schedule. The time tables are carefully 
 worked out so as to allow the necessary interval 
 between trains ; branch line trains are timed to 
 arrive at junctions just when there is a suitable 
 interval in the main line traffic, and so on. So long 
 as every train is able to keep time correctly there is 
 little need for any other form of control. The control 
 is really exercised when the time tables are drawn up. 
 
 215 
 
TRAFFIC CONTROL 
 
 In actual practice, of course, all manner of things 
 happen to cause delay to trains, delay which it is 
 quite impossible to foresee. Fog may settle over a 
 large area and disorganize all the traffic. Or it may 
 affect a small area with almost equally bad results, 
 for delay in one spot soon makes its results felt all 
 over a large system. The same may follow from a 
 small defect in some signalling apparatus or some 
 part of the permanent way. 
 
 As an example of this, one day, some years ago, 
 a passenger threw a small article out of a carriage 
 window near a small station on the south coast of 
 England. It happened to fall on the points of a 
 branch line, so that when the signalman tried to 
 operate them from his cabin he could not do so, but 
 had to send to see what was the matter and put it 
 right. This only took a few minutes, but it was 
 long enough to delay a train, and that delay made 
 itself felt as far away as the London Terminus of 
 the line. 
 
 Thus we see that as soon as anything goes a little 
 wrong, a thing which may easily happen, the need 
 arises for some mind or minds to take control and 
 readjust the arrangements to suit the new con- 
 ditions. 
 
 In this the stationmasters play a large part. The 
 traffic passing through a station is very largely under 
 the stationmaster's control. He has authority to do 
 what may seem to him at the moment the best, 
 having regard to the smooth working of the line as 
 a whole. The signalmen, too, have a considerable 
 discretion left to them under certain conditions, so 
 
 216 
 
TRAFFIC CONTROL 
 
 Mi, -it, they also can do their part in rectifying un- 
 expected difficulties. 
 
 The weakness with this form of control is, however, 
 that each official can only know what is happening 
 on his own piece of line. Roughly speaking, all ] 
 can do is to get the traffic along as expeditiously as 
 possible, leaving the men further on to do the best 
 they can with it in turn when it reaches them. A 
 certain amount of collaboration is possible by tele- 
 phone, but not a great deal. 
 
 Still, this form of control by stationmasters and 
 signalmen is perhaps sufficient for passenger traffic, 
 for there the regularity of the service removes many 
 difficulties. With goods traffic, however, it is quite 
 different. 
 
 Some goods trains, it is true, run to schedule just 
 as the passenger trains do, but a great many are in 
 effect " specials," running when needed. Even 
 those which are scheduled often have to stop at 
 wayside stations to pick up or to put off wagons. 
 Most of us at some time or other have seen a goods 
 train come along to some small station, proceed 
 to shunt a few trucks into one siding, a few into 
 another, pick up some from a third and, indeed, 
 perform quite a complicated series of movements 
 before once again resuming its journey. Obviously, 
 such operations cannot be allowed for accurately 
 in a time table, because the amount of shunting 
 necessary at each place probably depends upon the 
 commercial activity at the moment of some local 
 brickworks, or stone quarry, or upon the quality of 
 the local farmers' crops. 
 
 217 
 
TRAFFIC CONTROL 
 
 Goods trains, therefore, often get out of step, so 
 to speak, with the regular stream of traffic and lose 
 their place in the procession. Such a train may 
 have to wait a long time in some siding until the 
 signalman has a chance to slip it in in a suitable 
 interval between two passenger trains. 
 
 In manufacturing districts and most of all in 
 colliery districts, where the goods and mineral 
 traffic is very heavy, the management of this irregular 
 traffic becomes very difficult, so much so that some 
 years ago the Midland Railway adopted a system 
 of control extending all over a very busy area, 
 operated from one central point. 
 
 A marvellous system of telephones was installed, 
 giving instant communication between the controller 
 in his central office and the signalmen at the wayside 
 stations all over the area. 
 
 In order that the trains might be easily identified, 
 each engine had its number painted upon it or upon 
 its tender in huge figures, large enough to be read 
 from any reasonable distance, a custom which has 
 since spread throughout most of the British railway 
 systems. 
 
 Seated, then, in his office, the controller moves the 
 trains about almost like a chess-player with his 
 " men." He knows at each moment within a mile 
 or so where a train is, can stop it or start it, divert 
 it to one line or another, just as seems to him best, 
 and by that means he can get the whole of the 
 traffic moving in the most expeditious manner. 
 
 Since then, the same system has been adopted 
 upon other lines, and even electric street railways 
 
 218 
 
TRAFFIC CONTROL 
 
 or tramways have in places adopted it in order to 
 deal quickly with obstructions and breakdowns. 
 
 Now it will be seen that the whole success of this 
 method of control depends on the telephone. It 
 must be so arranged that the controller is in constant 
 touch with his men all over his area ; he must be 
 almost as free to speak to them and they to him as 
 if they were assembled in the same room. The 
 original installation on the Midland achieved this 
 
 5 
 
 SELECTION KEYS IN SELECTORS (N CABINS AT 
 
 CONTROLLERS OFFICE WAYSIDE STATIONS 
 
 Fig. 17. 
 
 This simple diagram shows how all the signal cabins in the 
 controlled area are connected to the Controller's Office by a 
 single pair of wires. 
 
 Key 1 sends out a certain series of impulses, to which only 
 Selector 1 can respond. In the same way, Key 2 calls up only 
 Selector 2, and so on. The controller's telephone is indicated 
 on the left. The local telephones are not shown each man 
 switches himself in when called by his selector. 
 
 by a multiplicity of lines and special code signals, 
 but since that was installed the need for a simpler 
 scheme has called into being one of the most wonder- 
 ful telephone systems ever invented. It was designed 
 by the Western Electric Company specially for this 
 particular purpose. 
 
 Let me introduce you to the G.N.R. Control Room 
 at Leeds. It is a large, airy apartment, not elaborately 
 furnished, but clean, warm and well suited for the 
 purpose. Along one wall is a large diagram showing 
 
 219 
 
TRAFFIC CONTROL 
 
 clearly the whole of that part of the Great Northern 
 system which is controlled from this station. 
 
 Facing this diagram, sit four men. Each has his 
 arm-chair and knee-hole desk, the desks being 
 spaced at equal distances opposite the long diagram. 
 Each of these men is a controller, and his duty is 
 to control the traffic upon the lines represented upon 
 that part of the diagram before which he sits. 
 
 Upon his desk, to his left hand, is a neat polished 
 wood case with rows of little turn-buttons on the front, 
 each button being distinguished by an ivory label. 
 
 Upon his head each controller wears a telephone 
 instrument similar to those worn by the operators 
 in a telephone exchange. 
 
 The diagram upon the wall is perforated with 
 small sockets into which can be pushed small plugs 
 with variously coloured heads ; each plug represents 
 a train, and the colour shows the kind of train, 
 whether passenger, goods, mineral and so on. Thus 
 the controller has always before him an actual repre- 
 sentation of the line with the positions of the trains 
 at any moment represented by the plugs, the 
 latter being, of course, changed continually as the 
 news comes in of the arrivals of the trains at the 
 successive points in their journeys. 
 
 As a train approaches the edge of an area the 
 controller for that area confers with his colleague 
 at the next desk, and ultimately hands the train 
 over to him. 
 
 Thus we see the operation of the system in the 
 control room. Let us now transfer ourselves to a 
 signal box in the controlled area. 
 
 220 
 
TRAFFIC CONTROL 
 
 A train approaches, the signalman goes to the 
 telephone and without any preliminaries just an- 
 nounces that train number so and so is passing. 
 There is no need for the signalman to ring up, for 
 the controller always has his headgear on, and any 
 signalman on a section can thus speak to him at any 
 moment almost as if they were in the same room. 
 
 On hearing of the passing of the train the con- 
 troller calls out the fact to a colleague, who makes 
 the necessary movement of a plug on the diagram. 
 Meanwhile, the controller is thinking, and he decides, 
 shall we say, that this particular train had better 
 be held up at the next station to give a faster train 
 precedence. He, therefore, puts out his left hand 
 and gives one of the turn-buttons a quarter -turn. 
 That is all he does, but the effect is that within a 
 few seconds he hears the signalman at the station 
 which the train is approaching " come on the line." 
 To him he gives the necessary instructions how he 
 is to dispose of the train when it reaches him. 
 
 Of course, the working of all the trains over a 
 large area is not completely represented by this 
 simple illustration. On the contrary, it is a very 
 complicated business, calling for a very clear head 
 and active brain, and the controller must be a man 
 of ingenuity, resource and quick decision. Still, the 
 illustration serves to give an idea of how the system 
 works. 
 
 Now the remarkable thing is that all this inter- 
 communication is entirely accomplished by means of 
 two wires. 
 
 These two wires run from the controllers' desk 
 
 221 
 
TRAFFIC CONTROL 
 
 through all the instruments at all the signal boxes 
 which come under his supervision. 
 
 All the instruments are connected in the same way 
 between these two wires, and were they ordinary 
 electric bells the effect of pressing a key in the con- 
 troller's office would simply be to ring them all. 
 It would, of course, be possible even then to use a 
 code of bell signals, thereby indicating which par- 
 ticular box was being called, the others hearing the 
 signal, but ignoring it. 
 
 That, however, would be a nuisance, for supposing, 
 say, thirty signal boxes on one circuit, each one 
 would, on the average, hear twenty-nine bell signals 
 to be ignored for every one that required attention. 
 There is another alternative, it is true, and that is 
 to have separate wires from the control room to 
 each signal box, but that entails very great expense, 
 not only when the wires are installed, but for upkeep 
 and repairs as well. 
 
 In this particular system both these difficulties 
 are overcome by the use of special " selective " 
 instruments. 
 
 The controller, as has been said already, has a 
 turn-button for each signal box. These are all 
 connected to the same two wires. When he gives 
 one a quarter-turn he thereby winds up a little 
 spring, so that when he lets go it slowly turns back 
 again. It is in turning back that it does its work. 
 The reason for this arrangement is that for effective 
 working it is desirable that it should turn at a regular 
 speed, and the uniform pressure of the spring ensures 
 this. No matter how quickly or how slowly the man 
 
 222 
 
TRAFFIC CONTROL 
 
 may turn the button, it comes back under the in- 
 fluence of the spring at a regular and unvarying 
 speed. 
 
 Now as it thus turns back it rotates a set of wheels, 
 like those of a stoutly made clock. The last of this 
 series of wheels moves the end of a little spring 
 finger, and this is so arranged that whenever a tooth 
 raises the finger a contact is made and a little current 
 of electricity goes to one of the pair of wires, through 
 ALL the instruments and back again along the other 
 wire. Likewise, whenever the end of the finger falls 
 into a space between two teeth it makes a momentary 
 contact and sends another current. 
 
 In conjunction with this there works a further 
 small device called a " pole changer relay," the 
 purpose of which is to cause these little currents to 
 flow alternately first in one direction and then in 
 another. 
 
 These currents are so short that it is perhaps 
 better to call them impulses, as the term current 
 gives the impression of a steady flow for some appre- 
 ciable time. 
 
 A relay is really an electrically operated switch, 
 its usual function being to enable a feeble current 
 to switch on and off a much more powerful current. 
 In this case, however, its purpose is to reverse the 
 connections with the battery. One impulse, passing 
 through the electro-magnet which forms a part of 
 the relay, pulls over a light switch into such a position 
 that the next impulse flows in the opposite direction. 
 
 The next impulse acts in the opposite way, thereby 
 undoing what the first one did, with the result that 
 
 223 
 
TRAFFIC CONTROL 
 
 the series of impulses sent out by the " selector key," 
 as the clockwork device is called, pass to the wire 
 alternately " positive " and " negative," as the 
 telegraph engineer terms it. 
 
 Thus the result of turning the button and then 
 letting it go is to send through the wires a series of 
 seventeen impulses. It is not quite clear why seven- 
 teen was chosen, but no doubt that was found to be 
 the most convenient number. 
 
 Alongside the wheel which sends out these impulses, 
 and capable of being clamped to it, are two brass 
 discs, each of which has a projection at one part of 
 its circumference. This projection coming into con- 
 tact with the " finger " causes it to be held still, 
 and thereby interrupts the regular flow of impulses. 
 Just where this interruption occurs in the series of 
 seventeen depends upon the position in which the 
 disc is clamped alongside the wheel. By fixing the 
 two discs in the correct positions, two intervals can 
 thus be produced at any desired points in the series. 
 
 The " selector keys " are, of course, in that neat 
 little cabinet on the controller's desk, and they are 
 all alike in every respect, except for the positions of 
 the discs. Each of them, when turned and then let go, 
 sends out a series of seventeen impulses, but in each 
 one the interruptions occur in different places. It 
 is the positions of the intervals which enable each 
 key to do its proper work. 
 
 Just to make this quite clear, let us consider a 
 few examples of seventeen impulses with two intervals. 
 We can commence with two impulses, pause, two, 
 pause, thirteen. Then would come naturally in 
 
 224 
 
5 
 
TRAFFIC CONTROL 
 
 sequence, two, pause, three, pause, twelve ; then 
 two, pause, four, pause, eleven, and so on to thirteen, 
 pause, two, pause, two. By varying the positions 
 of the pauses as many as seventy-eight different 
 " signals " can be made. 
 
 And now let us pass to the " selectors," of which 
 there is one at every signal box. All of them are 
 connected in precisely the same way between the 
 two wires, so that each impulse sent out by a key 
 divides itself up and passes equally through all. 
 
 Thus every time a key is operated all the selectors 
 work, but only one rings a bell. 
 
 This apparently miraculous result follows from the 
 position of the pauses in the series of impulses sent 
 out by the key. 
 
 The selector has, first of all, an electro-magnet, 
 composed of a soft iron core encircled by a coil of 
 insulated wire. This is normally powerless, but is 
 energized whenever a current of electricity passes 
 through it. 
 
 Against the end of the core is set a permanent 
 magnet, that is to say, a piece of steel which has been 
 so treated that it has the properties of a magnet 
 permanently. Such a magnet, as most people know, 
 has a North Pole and a South Pole. What the 
 difference is nobody knows precisely, but we do know 
 that there is a difference, and one of the most im- 
 portant manifestations of this " polarity " is that 
 if two magnets be brought near each other, similar 
 poles will repel each other, while dissimilar poles 
 will attract each other. 
 
 The poles of a permanent magnet remain fixed ; 
 p 225 
 
TRAFFIC CONTROL 
 
 the poles of an electro-magnet change according to 
 the direction of the current through the coil. There- 
 fore, if we set one pole of a permanent magnet 
 against one pole of an electro-magnet we can cause 
 the latter to attract or repel the former at will by 
 simply changing the direction of the current. 
 
 An arrangement of that sort is found in the 
 " selector," and the little impulses coming from the 
 key, because of their alternate directions, alternately 
 push and pull upon a small permanent magnet 
 mounted near. 
 
 The next feature which demands our attention is 
 a small wheel, like a wheel of a clock, which is mounted 
 upon a vertical axis near to the magnet. When the 
 magnet moves one way a little ringer attached to it 
 comes into contact with one of the teeth of the wheel 
 and pushes it round a little way. On the current 
 being reversed the permanent magnet moves the 
 opposite way, and that is made to operate another 
 finger which again gives a push to the wheel, so that 
 with each impulse the wheel is rotated one tooth. 
 
 In their normal position both these fingers are 
 just clear of the wheel, so that the wheel can turn 
 freely ; moreover, there is a spring which is always 
 trying to pull the wheel back to its normal position, 
 so that at first sight it seems as if the fingers would 
 do no work at all. We might expect that when the 
 first finger had given its push, as it drew back, the 
 wheel would also turn back, and the second finger 
 would only do over again what the first had done. 
 The inertia of the wheel, however, comes in here. 
 The first finger pushes the wheel, then it suddenly 
 
 226 
 
TRAFFIC CONTROL 
 
 draws back and the second gives its push, and the 
 second follows the first so quickly that the wheel has 
 not time to swing back. The second finger catches 
 the wheel practically in the position where the first 
 leaves it, and so the two acting alternately can push 
 it round to the extent of seventeen teeth, if they 
 continue to follow one another sufficiently rapidly. 
 
 But when a pause occurs in the series, the wheel, 
 as it is easy to see, will swing back to its starting 
 point. 
 
 We now come to the next essential feature in the 
 selector. In addition to possessing teeth, the wheel 
 has a series of small holes all round its edge, and in 
 any of these a small pin can be fixed. As a matter 
 of fact, in each one two pins are placed, and they are 
 so placed as to correspond with the pauses in the 
 impulses sent out by the corresponding key. 
 
 To complete the device, there is a light catch which 
 is able to lay hold of one of these pins, and hold it 
 sufficiently to prevent the wheel swinging back. 
 
 We now have in our mind's eye a picture of all the 
 important parts in the selector, and can, in imagina- 
 tion, watch it at work. 
 
 For this purpose, let us suppose that a certain 
 selector key sends out the following series of im- 
 pulses : namely, 4, 6, 7, and let us watch these 
 impulses coming into a selector which they are not 
 intended to operate. 
 
 The first impulse rotates the wheel to the extent 
 of one tooth, the second pushes it a further one, 
 making two, the next turns it to three and the next 
 to four ; then the pause occurs, during which the wheel 
 
 227 
 
TRAFFIC CONTROL 
 
 slips back to its starting point. Then the six impulses 
 follow, turning the wheel six teeth, after which it 
 slips back once more ; finally it turns seven teeth 
 before slipping back a third time. 
 
 At the selector which is set to respond to that 
 particular signal the result is quite different. The 
 four impulses come along and act just as they did in 
 the former case, but the fourth brings a pin into 
 engagement with the catch, and so the wheel is held 
 throughout the pause. The six impulses then come 
 along and carry the wheel round to its tenth tooth, 
 at which point the second pin comes into engagement 
 with the catch, so that the wheel is held during the 
 second pause, after which the seven impulses follow, 
 carrying the wheel round to the seventeenth tooth. 
 
 Now when the seventeenth tooth is reached an 
 arm carried upon the wheel makes contact with a 
 stud and rings a bell. 
 
 So whenever a key is turned a series of impulses 
 goes forth to all the selectors. All respond, but only 
 one is able to reach the seventeenth tooth and ring 
 the bell. All the others, since their pins do not 
 correspond with the pauses, at some time or other 
 slip back. 
 
 Usually there is one key in the controller's cabinet 
 in which the wheel has no discs alongside of it. 
 Therefore it sends out an uninterrupted series of 
 seventeen impulses, the result being that that par- 
 ticular key calls up all the signal boxes, a useful 
 arrangement when the controller wants to send out 
 general information of interest to all the men. 
 
 The controller, therefore, by means of an operation 
 
 228 " 
 
TRAFFIC CONTROL 
 
 which takes up three seconds, can call up any signal 
 box or all. It is not necessary for them to be able to 
 ring him up since he has always got his headgear on, 
 so that they only need to speak and he will hear. 
 
 Should he at any time for a special reason have 
 to take off his headgear he can switch on a loud- 
 speaking telephone, the sound of which will be loud 
 enough for him to hear in any part of the room. 
 
 It seems as if it would be impossible to improve 
 upon this system, so simple and yet so effective. 
 There are but two wires, yet controller and signalmen 
 are so closely in touch at every moment throughout 
 the day that they might almost be in the same room. 
 
 229 
 
CHAPTER XVII 
 THE TUBE RAILWAY 
 
 ONE of the most modern features in the railway 
 world is the " tube " form of construction for 
 lines traversing populous places. 
 
 Tunnels are, of course, a very old idea. Tunnels 
 were made centuries ago to carry aqueducts, and 
 later to carry navigation canals. Then followed 
 the railways, and tunnels were made all over the 
 world. In most cases these were through hills and 
 mountains, the heights of which were too steep to 
 climb and the bases of which were too broad to go 
 round. 
 
 In time there arose the need for local lines serving 
 the great towns, carrying passengers in and out 
 between the central portions and the suburbs, and 
 these in many cases necessitated tunnels in order 
 that the town should not be cut up by the lines or 
 valuable sites of buildings destroyed. 
 
 Thus many large cities have examples of railways 
 in tunnels just below the surface. These generally 
 follow the line of the public roads, and one of the 
 great difficulties in their construction was the diver- 
 sion of the sewers and underground pipes, which 
 led to the idea of boldly diving down below the lowest 
 of the pipes and making the tunnel in virgin soil, 
 
 230 
 
THE TUBE RAILWAY 
 
 practically in a new world, a world which had not 
 (except at a few isolated points) been penetrated 
 since the formation of the globe. 
 
 For this purpose there was brought into play, in 
 a new and improved form, a device called a " shield." 
 It was not a new idea, for it had been used by Brunei 
 in making the first tunnel under the Thames early 
 in the nineteenth century. 
 
 Most readers will at some time or other have 
 watched the family cook making mince pies, and will 
 have seen her cutting out round pieces of paste by 
 means of a circular cutter, consisting of a ring of thin 
 metal with a sharp edge which, being pressed upon 
 the paste, cuts a neat round disc. 
 
 Brunei hit upon this method for cutting a way 
 through the London clay beneath the bed of the 
 Thames. 
 
 His shield was not round, but square, but it acted 
 in the manner of the paste cutter in that it was 
 forced slowly forward, while men working inside it 
 dug away the earth which it enclosed. 
 
 The modern tubes are circular, so that the shield 
 used for them is still more like the cook's little cutter. 
 
 Imagine a steel drum a dozen feet or so in diameter 
 and of just about the same proportions as the familiar 
 side-drum of a band. Like the side-drum, too, it 
 has in some cases two skins, but of steel instead of 
 parchment. The skins are perforated by holes and 
 doors ; there are, moreover, floors and partitions 
 between the two " skins " and in front of the fore- 
 most one. 
 
 Before the shield can be brought into use, of 
 231 
 
THE TUBE RAILWAY 
 
 course, a shaft has to be sunk to the required depth 
 from which the shield can bore its way. This shaft 
 is dug out and lined with a complete lining of iron, 
 formed of cast-iron segments accurately fitted to- 
 gether and connected by bolts and nuts. 
 
 In some cases the weight of this lining has to be 
 sustained temporarily by rods from above in order 
 that successive rings of plates may be added under- 
 neath. In others the weight of the lining is made 
 to help with the excavation, a sharp -edged ring 
 being placed at the bottom which cuts its way down 
 as the enclosed earth is removed from the inside. 
 In such a case the rings are added at the top as the 
 whole thing descends. 
 
 In other cases, again, where water is encountered, 
 the upper end of the shaft is covered in with an air- 
 tight cover, through which air is forced by com- 
 pressors in order to keep the water back. 
 
 Where that is done access to the lower part of the 
 shaft is through pairs of doors which constitute 
 " air-locks." 
 
 Everyone has seen locks on a canal or dock, and 
 knows that they consist of two doors or pairs of doors, 
 one of which holds back the water while the other 
 is open, thereby allowing vessels to pass through 
 without letting through more than a small quantity 
 of water. In like manner does an air-lock work ; one 
 door holds back the air while a second one is open, 
 so that men and materials can be passed through 
 without letting through more than a very small 
 quantity of air. 
 
 To pass through an air-lock from the open air, a 
 
 232 
 
 
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 it 
 
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 2 g 
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 ^ be 
 
 e .3 
 
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THE TUBE RAILWAY 
 
 man opens the first door, enters, closes the door 
 behind him and then waits while the air from the 
 " pressure " side of the lock is allowed to trickle 
 through and slowly raise the pressure between the 
 doors. When that has been done he opens the 
 second door and passes through. 
 
 Coming out, the procedure is reversed, the man 
 having to wait in the lock while the pressure is slowly 
 allowed to fall to that of the atmosphere. 
 
 This slow change of pressure is important for the 
 health of the men who have to pass through fre- 
 quently. With care, however, and under reasonable 
 pressures, there is nothing to fear. 
 
 Readers may perhaps be tempted to wonder why 
 the change in pressure of air should need to be thus 
 gradual. As far as one can see the ear-drum is the 
 only thing likely to be much affected, but that is 
 not so. There is communication with the outer air 
 on both sides of the drum of the ear ; one through 
 the outer ear and the other through a tube into the 
 mouth and so through the nostrils. If this little 
 tube, called by doctors the " eustachian tube," be 
 for any reason stopped up, then the air pressure will 
 increase on one side of the " tympanum " faster 
 than on the other, and a severe pain will be felt, 
 but otherwise the pressure changes equally on both 
 sides, and the ear-drum is in no way affected. 
 
 The real trouble lies in the blood. Like all other 
 liquids, the blood is able to absorb a certain amount 
 of gas, the amount depending upon the pressure. 
 
 This fact is the basis of the manufacture of mineral 
 waters. Soda water is simply water which has been 
 
 233 
 
THE TUBE RAILWAY 
 
 brought into contact with a gas under pressure. A 
 certain amount of the gas is absorbed, and so long 
 as the pressure is maintained (as it is so long as the 
 stuff remains in the bottle) it looks just like ordinary 
 water. When you take the cork out, however, the 
 pressure drops, the amount of gas which the water 
 can hold drops too, and the surplus gas comes 
 bubbling out. The " fizzy lemonade," beloved of 
 boys, is just the same thing flavoured with lemon, 
 so that the drink so popular on a hot day owes its 
 special feature to this fact. 
 
 Now, however good " fizzy " lemonade may be, 
 " fizzy " blood is not healthy. Under pressure, 
 the gases of the atmosphere are absorbed by the 
 blood, particularly the nitrogen, and on the pressure 
 falling this bubbles out, and if that take place 
 rapidly certain blood-vessels and parts of the heart 
 may become clogged, so to speak, with nitrogen. 
 It is only necessary to picture this to realize that it 
 must be very desirable to lower the pressure gradually 
 in order that the liberation of the nitrogen shall take 
 place slowly. 
 
 Let us assume, then, that the shaft is finished. 
 The next thing is to determine the precise direction 
 which the shield must follow. This is known, of 
 course, upon the surface, and it is only a question of 
 transferring that direction to the bottom of the 
 shaft. 
 
 This requires the most scrupulous care, because a 
 very slight error to commence with would result in 
 the tunnel, as it progressed, straying a long way out 
 of its proper course. The means employed, however, 
 
 234 
 
THE TUBE RAILWAY 
 
 is very simple. A beam is laid across the mouth of 
 the shaft in the precise direction which the tunnel is 
 to follow. Then two pieces of piano wire are sus- 
 pended from this, with heavy weights on their lower 
 ends. By sighting across these two wires the engineers 
 get their starting direction at the bottom of the 
 shaft. After that they have to depend upon the use 
 of the steel tape and the theodolite. 
 
 Referring to the plan of the route as set out upon 
 the surface, the engineer knows that from the start 
 the tunnel runs so far in a perfectly straight line, 
 then turns, let us say, three degrees to the right. 
 The tunnel is, therefore, made straight for the 
 required distance, upon reaching which he sets up 
 his theodolite at the point where the change occurs, 
 sights the telescope which forms a part of the theodo- 
 lite back upon his starting point, and then turns it 
 " so many " degrees, which gives him the new 
 direction, and so he goes on. 
 
 In the same way the engineers have to watch the 
 levels, for which again the theodolite is employed. 
 
 In case there should be any readers not familiar 
 with this valuable instrument it may be well to 
 explain that it consists of a small telescope fitted 
 upon a tripod, and combined with two circular scales 
 for measuring angles. Across the lens of the tele- 
 scope is a fine thread or " wire," so arranged that 
 when an observer looking through the telescope sees 
 a point apparently cut in two by the wire he knows 
 that the instrument is pointed directly at it. 
 
 If, then, he changes the direction of the telescope 
 and points it at something else, he can read off, on 
 
 235 
 
THE TUBE RAILWAY 
 
 one of the scales, through how many degrees and 
 parts of a degree he has turned it. One scale shows 
 how far it has turned in a horizontal plane and the 
 other how far it has turned in a vertical plane, so that 
 he can measure the rise and fall as well as the deviations 
 to right and left. 
 
 This question of rise and fall is just as important 
 in the case of tunnels as the direction in a horizontal 
 plane, for it would evidently be as troublesome if a 
 tunnel got on to a wrong level as it would be if it 
 got a wrong direction. 
 
 It is usual in most cases to start at two or more 
 shafts and work the tunnels until they meet, the 
 measurements being generally so correct that an 
 error of an inch or two is regarded as quite large. 
 
 In one respect the designer of a tube railway has 
 an advantage over his colleague who has to lay his 
 lines upon the surface. The latter is compelled to 
 a great extent to follow the gradients of the land. 
 True, he may make a cutting here and an embank- 
 ment there, but generally speaking he has to follow 
 the lie of the land. The " tube " man, however, can 
 go up or down just as he likes, and he takes advantage 
 of this to help the traffic. 
 
 As a train leaves a tube station the line descends 
 so as to help it to accelerate, in other words, to get 
 up speed. Likewise, the tube train always approaches 
 a station uphill, thereby saving brake power. The 
 two lines are always in separate tunnels, so that to 
 each can be given just the right inclination at each 
 point. The lines are not by any means always side 
 by side ; it may happen that one is above the other, 
 
 236 
 
THE TUBE RAILWAY 
 
 even right on top of it. All these matters are deter- 
 mined by the circumstances of the particular case ; 
 they are not done haphazard, but after the most 
 careful consideration of the facts. 
 
 But we have been getting on rather too fast. Let 
 us suppose that we have completed a shaft and 
 lowered the shield down to the bottom. The iron 
 lining of the shaft will have a circular opening 
 formed in it which will in time constitute the mouth 
 of the tunnel. To this opening the shield is carefully 
 adjusted, and then tunnelling operations proper 
 commence. 
 
 The shield is pushed forward and its sharp edge 
 cuts into the earth, while men passing through to 
 the front commence to dig away the earth. Under 
 favourable conditions no air pressure is needed, but 
 generally it is found useful to have a little pressure 
 in order to hold up the earth at the " face," or part 
 where the men are working, and to prevent it from 
 falling away too readily. When that is so an air-tight 
 bulkhead is formed at some convenient point behind 
 the shield and air is pumped in to keep up the re- 
 quisite pressure. 
 
 In these circumstances the openings in the dia- 
 phragm of the shield can be left open, and the men 
 and materials pass freely through. Under less 
 favourable conditions, however, when water is 
 present, the doors in the two diaphragms of the 
 shield are made to form air-locks, and a higher 
 pressure is maintained between the shield and the 
 face than that between the bulkhead and the shield. 
 
 This air-pressure question is often a very difficult 
 
 237 
 
THE TUBE RAILWAY 
 
 one, particularly when passing under a river, because 
 the pressure sufficient to keep the water out at the 
 bottom of the tunnel may be more than is good at 
 the top of the tunnel. If the layer of earth above 
 the tunnel be thin the air pressure, if not properly 
 managed, may even blow up the bed of the river. 
 During the construction of the Bakerloo tube under 
 the Thames there was one spot where air was escaping 
 up through the river bed night and day for months. 
 
 In this case it was possible to keep things safe by 
 having the air-pumps always going, but in others 
 it may be necessary to put a patch, so to speak, 
 upon a weak spot in the bed of the river, by tipping 
 boatloads of clay upon it. 
 
 In some cases the excavation is all done by hand, 
 but in others an " excavating shield " is employed. 
 
 In this a huge wheel with scoops on its edge is 
 fixed to the face of the shield and driven round by 
 an electric motor. The scoops cut away the earth 
 and then drop it through shoots to the back of the 
 shield. 
 
 Another adjunct of the simple shield is an arm 
 worked by hydraulic power, which lays hold of the 
 iron segments with which the tube is lined and lifts 
 them into their places. 
 
 Furthermore, to the hinder edge of the shield 
 there are fixed a number of hydraulic rams, which 
 push against the ring of segments last fixed, thereby 
 propelling the shield along. 
 
 The joints between the segments are made with 
 strips of thin wood, carefully impregnated before- 
 hand with creosote. These are put in before the rings 
 
 238 
 
THE TUBE RAILWAY 
 
 are bolted together, so that when the bolts are 
 tightened up they are gripped tightly. 
 
 In the centre of each segment there is usually 
 left a hole, through which a mixture of cement and 
 sand is squirted by means of a compressed air squirt, 
 commonly referred to by the workmen as a " gun." 
 The mixture is made with plenty of water, so that it 
 is very fluid, and it fills up all the little cavities left 
 between the iron and the earth. This liquid, by the 
 way, is called " grout." 
 
 The stations are enlargements of the ordinary 
 tunnels. They, too, are circular, and are lined with 
 iron segments. Usually they are cut out by hand 
 after the smaller tunnel is made. The latter is run 
 right through in the first instance and the enlarge- 
 ment made afterwards. This seems a waste of time 
 and labour, but is found in practice to be the best 
 method. 
 
 One of the original ideas in the construction of the 
 tubes was to make them self-ventilating. It is sur- 
 prising how reluctant even a light thing like air is 
 to being pushed about. 
 
 Anyone familiar with mines knows the huge 
 engines and fans which are necessary to keep the air 
 moving in the workings, and something of the sort 
 would be necessary in the tubes but for the action 
 of the trains themselves. 
 
 The train nearly fills the tube, so that as it moves 
 along it tends to push the air along with it. The 
 effect of this is very noticeable in some of the 
 tubes, where the approach of a train is heralded, a 
 long time before it actually arrives, by the strong 
 
 239 
 
THE TUBE RAILWAY 
 
 current of air which it drives through the tube and 
 often up the shafts at the stations. 
 
 For a time the earlier tubes had an earthy smell, 
 which was not pleasant. They could not get rid of 
 the peculiar atmosphere which arises from newly 
 dug earth, but the excellent ventilation has by 
 now largely removed this, particularly where it is re- 
 inforced by the use of artificial " ozone," as described 
 elsewhere. 
 
 In thinking over the tubes and their construction 
 it is impossible to avoid being struck by the simple, 
 common-sense methods by which they are formed. 
 It required, none the less, great thought (not to say 
 genius) and the most scrupulous care, on the part 
 of engineers and workmen, before they could be 
 made with the certainty and ease with which they 
 can be made to-day, and we are quite right in re- 
 garding them as one of the wonders of our age. 
 
 240 
 
 
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CHAPTER XVIII 
 WONDERS OF THE UNDERGROUND 
 
 THERE is not a more remarkable group of rail- 
 ways in the world than those controlled by the 
 Underground Railways of London, Limited. 
 Indeed, it is doubtful if they are equalled. 
 
 The group comprises the Metropolitan District 
 Railway and about half a dozen " tubes." In addi- 
 tion the company controls thousands of motor 'buses 
 and miles of electric tramways, but we are only con- 
 cerned here with the railways. 
 
 The District Railway is the one which Londoners 
 for many years referred to as " The Underground." 
 One part of it, together with a part of the Metro- 
 politan Railway and a short piece of line owned 
 jointly by the two companies, forms roughly a circle, 
 and around this trains run continually all day long. 
 This route is known as the " Inner Circle." 
 
 Practically the whole of the Inner Circle is under- 
 ground, but it is different from the tubes in that the 
 tunnels are only just beneath the surface. They were 
 made many years ago by the simple method of " cut 
 and cover," which means that a cutting was first 
 made, open to the sky, and this was then covered 
 over with a strong roofing of brick arch, upon the 
 Q 241 
 
WONDERS OF THE UNDERGROUND 
 
 top of which a roadway was laid or, in some cases, 
 buildings were erected. 
 
 For years it was worked by steam locomotives, 
 and while it was very convenient in those days, com- 
 pared with the horse 'buses above, the trains were slow 
 and few compared with the remarkable services of 
 to-day. Moreover, the smoke from the engines 
 caused the atmosphere in the tunnels to be very 
 unpleasant. 
 
 Starting from the Inner Circle are a number of 
 branches to various suburbs. All of these rise into 
 the open air when they reach the less crowded areas. 
 
 The old Underground was a fine piece of engineering 
 in its day, and does honour to the men who built it 
 and worked it. 
 
 The next stage in underground railway construc- 
 tion was marked by the formation of the City and 
 South London Railway, from the Monument, near 
 London Bridge, to Stockwell. It was the first of the 
 tubes, entirely underground, at a level sufficiently 
 low to pass under everything else ; it was reached by 
 lifts as well as stairs, and its means of ventilation were 
 so limited that before the days of electric traction it 
 would have been impossible to work it. 
 
 This, too, was in its time a great success, although 
 its later imitators have improved upon many of its 
 features. It was followed by the Central London, also 
 a deep-level tube, from the Bank to Shepherd's Bush, 
 since extended in both directions. Later came the 
 Waterloo and City, the Baker Street and Waterloo 
 (now known as the Bakerloo), the Great Northern, 
 Piccadilly and Brompton, the City and Great Northern 
 
 242 
 
WONDERS OF THE UNDERGROUND 
 
 and the Hampstead tube. All these latter are deep- 
 level tubes and are very similar in construction except 
 the Great Northern and City, which is large enough 
 to take ordinary railway stock. 
 
 It was about half-way through this tube-building 
 era that a wonderful man from the United States, 
 Mr. C. J. Yerkes, suddenly burst upon the astonished 
 Londoners with the news that he had in effect bought 
 the District Railway, never a very prosperous one 
 financially, and was going to electrify it and bring it 
 up-to-date. Later he brought tube after tube under 
 the same management until, now, the whole of the 
 lines mentioned except three are grouped together, 
 and while to some extent retaining their separate 
 existence, are all controlled and worked as one system 
 by the Underground Railways of London. 
 
 The three exceptions are the Metropolitan, which 
 although closely allied remains quite independent, 
 the Great Northern and City, which has been merged 
 into the Metropolitan, and the Waterloo and City, 
 which belongs to the London and South Western 
 Railway Company. 
 
 The efforts of Mr. Yerkes were crowned with 
 brilliant success, from the point of view of the 
 traveller, at all events ; what the financial result 
 has been is not our business here. 
 
 Technically speaking, the chief points of interest 
 about these lines are the electric traction, the method 
 of constructing the tubes and the automatic signalling, 
 but all these things are dealt with in other chapters. 
 Here we will consider some of the other features 
 which in one sense are only minor ones, but which 
 
 243 
 
WONDERS OF THE UNDERGROUND 
 
 from the standpoint of the public are of great im- 
 portance and which are characteristic of these wonder- 
 ful lines. 
 
 The managers of the " Underground " have, from 
 the very first, taken a more sympathetic attitude 
 towards their passengers than is customary on rail- 
 ways. 
 
 It must be confessed, with all due admiration for 
 those who run railways in general, that there is a 
 tendency with many of them to think that if a 
 passenger is in any doubt, " well, he must ask some- 
 body." The Underground people try to keep him 
 from ever being in doubt ; to make his path so plain 
 and easy that he can hardly go wrong. 
 
 Let us examine what may be termed the out- 
 standing example of this : Suppose you go on to, 
 let us say, the " westward-bound " platform at 
 Westminster Bridge station on the District line, and 
 we will imagine that you want to go to Baling. In 
 a most prominent position you will see an indicator. 
 You can hardly fail to see it, so well placed is it. 
 There you will see something like this : 
 
 EALING 
 WIMBLEDON 1 
 INNER CIRCLE 
 
 3 
 2 
 
 FIG. 18. 
 
 The names are in bright white letters on a blue 
 ground and the figures are illuminated by electric 
 lights. From this you will notice that the train you 
 
 244 
 
WONDERS OF THE UNDERGROUND 
 
 want will be the third one in, the first being 
 for Wimbledon and the second for the Inner 
 Circle. 
 
 Presently a train comes in and after a short stop 
 passes out again. As it leaves the station a change 
 suddenly comes over the indicator. The 1 disappears 
 from Wimbledon and appears against Inner Circle. The 
 2 disappears from Inner Circle and appears against 
 Ealing. The 3 disappears from Baling and appears 
 against some other route. 
 
 Every time a train passes out of the station that 
 happens ; the numbers changing so that all through 
 the day the next train, the one after and the one 
 after that are indicated on the platform. 
 
 Now the remarkable thing is that, owing to the 
 signalling being automatic, there is no signalman to 
 operate this indicator at Westminster Bridge. How, 
 then, does the indicator know what trains are to be 
 expected and their precise order ? 
 
 To answer this question we need to go back four 
 stations in an easterly direction, to the Mansion 
 House, where, owing to the presence of sidings, a 
 signalman is necessary. All the trains which pass 
 Westminster Bridge in a westerly direction either 
 originate at the Mansion House or else pass through 
 there. 
 
 Let us imagine that we are in the signal box at the 
 Mansion House station first thing in the morning, 
 and that the first train of the day is about to leave. 
 The signalman, by the movement of a handle upon 
 an instrument, sends a message right along the line to 
 every station as far as South Kensington, where the 
 
 245 
 

 WONDERS OF THE UNDERGROUND 
 
 next signal box is, giving the destination of the first 
 train. 
 
 In due course he sends another and another. Each 
 train as it leaves his station is announced by him to all 
 the others. 
 
 At each of the other stations there is an instrument 
 which is termed a " magazine," a sort of mechanical 
 memory, which notes down these announcements, as 
 it were, for future reference. At any moment the 
 magazine at one of these stations knows what trains 
 have left the Mansion House and in what order they 
 have left. 
 
 The indicator at the station is operated automatic- 
 ally by each train as it leaves the station, and what it 
 does is to publish the list of the next three trains, 
 based upon the information stored up in the magazine. 
 It seems almost too human to be possible in a mere 
 mechanism, but it is a fact, and these instruments 
 have been working day in and day out for years and 
 seldom do they make a mistake. 
 
 The indicator itself is a very simple arrangement. 
 The names of the various routes are simply enamelled 
 iron like the familiar advertisements to be seen along 
 all railway lines and like the street name-plates used 
 in many towns. Against the end of each there is a 
 piece of sheet metal with the figures 1, 2 and 3 cut 
 out stencil fashion, and behind each of these figures 
 is an electric bulb. In the front of the figures is placed 
 a piece of frosted glass, with the result that they are 
 invisible unless illuminated by the light, so that 
 by switching on one of the three lights one of the three 
 figures can be made visible. 
 
 246 
 
WONDERS OF THE UNDERGROUND 
 
 The " magazine train describer," or mechanical 
 memory, is a truly wonderful instrument. The basis 
 of it is a hollow metal drum mounted upon a 
 spindle. There is also a rachet arrangement whereby 
 it can be turned round by a series of equal steps. 
 This is actuated by an electro-magnet so that an 
 electric impulse can operate it. 
 
 The describer is constructed to hold a record of 
 fifteen trains, and so the drum needs fifteen impulses 
 to cause one complete revolution. At each impulse 
 it moves one-fifteenth of a revolution. 
 
 Across its edge there are fifteen rows of small holes 
 (4 in each), the rows being equally spaced all round. 
 In each of these holes there slides a little iron peg, the 
 position of which is normally such that it projects on 
 the outside and is flush on the inside. 
 
 Fixed to the stationary part of the apparatus is a 
 row of little hammers, four in number, so placed that 
 each one is opposite a peg. These hammers are 
 actuated by electro-magnets so that they can re- 
 spond to short currents of electricity. 
 
 When the signalman at the Mansion House wishes 
 to describe a train he moves a pointer round a dial 
 until it points at a little tablet on which are inscribed 
 the words that he wants to send. Then he presses a 
 push. That sends current through all the describers, 
 and in each it actuates one or more of the hammers. 
 
 Let us take the case of that particular train the 
 signal for which is a current on No. 1 line only. Then 
 all the No. 1 hammers will act, will strike the No. 1 
 pegs and drive them in so that they project on the 
 inside of the drum. 
 
 247 
 

 WONDERS OF THE UNDERGROUND 
 
 Likewise if the signal is No. 2 the current will pass 
 along No. 2 line and the No. 2 hammers will act. 
 The same with 3 and 4 or any combination. 
 
 When the hammers have driven in a peg or pegs 
 on each drum, the drums all turn automatically so 
 that the next row of pegs are presented to the ham- 
 mers ready to receive the next description. 
 
 Thus the drum, with some of its pegs driven in and 
 some normal, constitutes a list of the approaching 
 trains and their destinations. 
 
 That brings us to another part of the mechanism, 
 the purpose of which is to read this list and communi- 
 cate it item by item to the indicator itself. 
 
 The " reader," as we might call it, consists of a 
 second drum, inside the first, with a row of four light 
 springs so placed that they just touch the ends of a 
 row of pegs when the pegs are driven in, but not when 
 they are normal. 
 
 At the commencement of the day, the peg or pegs 
 first driven in make contact with the springs and so the 
 first train is announced. As further signals come in 
 and subsequent rows of pegs are acted upon by the 
 hammers, so the whole thing turns round step by 
 step, but since the two drums move together the 
 indicator still announces the first train, for the springs 
 still remain in contact with the first row of pegs. 
 
 When a train passes, however, it turns the inner 
 drum one step in a backward direction, so that it brings 
 the springs into contact with the second row of pegs. 
 
 To put it another way, the inner drum reads off 
 the first item on the list and continues to do so, no 
 matter how many items may be added, until a train 
 
 248 
 
I 
 
 60 
 
 "S rt 
 
 ri 
 
 a 
 
 2 cu 
 
 .u a 
 
 "I 
 
 o ^ 
 .u "5 
 
 a 
 
 O 'J 
 
 
 
 ' 
 
 o 
 
 O 43 
 
 a o- 
 
WONDERS OF THE UNDERGROUND 
 
 turns it back a step, after which it reads off the second 
 item. In due time a second train passes, it turns back 
 once more and then reads off the third item, and so it 
 goes on throughout the day. 
 
 But the indicator, you will remember, shows three 
 trains and not merely one. This is arranged for by 
 the simple expedient of having three sets of springs, 
 the first of which controls the figure 1 on the in- 
 dicator, the second the figure 2 and the third the 
 figure 3. 
 
 There is still one step, however, to be explained. 
 How do the springs on the inner drum know how to 
 select that particular line on the indicator where they 
 have to exhibit the number ? In other words, how 
 are they able to translate the signal as it is registered 
 upon the outer drum into plain English ? 
 
 This is done by a further instrument called a 
 " combinator," which may be described as an 
 elaborate form of relay which is mentioned in another 
 chapter. It is so arranged that current from No. 1 
 spring completes a circuit and allows current to flow 
 to a certain lamp in the indicator ; current from No. 
 2 sends it to another lamp ; current from Nos. 1 and 2 
 together to a third, and so on. Thus it translates 
 the signals recorded by the in-driven pegs into 
 language which the public can understand. 
 
 After a row of pegs has done its work it passes a 
 row of electro-magnets which pull out any that have 
 been driven in, and thus the " slate is cleaned," ready 
 for a new item to be added to the list. 
 
 At some stations there are platforms where trains of 
 the same sort may come in on either side, and it is 
 
 249 
 
WONDERS OF THE UNDERGROUND 
 
 desirable to show passengers which side to expect 
 the train for which they are waiting. 
 
 In such cases similar indicators are employed, 
 except that instead of the numbers there are two 
 arrows, one pointing to one side of the platform and 
 one to the other. 
 
 The operation of these is comparatively simple. 
 The two arrows are cut out, like stencils, in an 
 opaque screen and illuminated from behind by 
 electric lamps. When the train is to come on the 
 right-hand platform the signalman turns on the 
 lights on that side and the arrow becomes visible, 
 while the arrow on the other side remains invisible 
 behind the frosted glass with which both arrows are 
 covered. When he wishes to indicate the other 
 platform he simply reverses the lights. 
 
 Another feature of the Underground is the moving 
 stairways, or escalators, at some of the stations. 
 
 These will no doubt be familiar objects to some 
 readers, but for the benefit of others it may be 
 explained that, when still, an escalator looks just 
 like any ordinary staircase. You can step on at the 
 bottom and walk to the top or vice versa, just as you 
 do on the stairs at home. 
 
 When at work, however, the stairs are continually 
 moving up or down, as the case may be, so that you 
 need only step on to a stair and stand there while 
 you are carried from top to bottom, or from bottom 
 to top. 
 
 Energetic people who are in a hurry are not 
 content to stand still upon the stairs and let them do 
 the work, but run up or down as if they were ordinary 
 
 250 
 
WONDERS OF THE UNDERGROUND 
 
 stairs, thus adding their own speed to that of the 
 stairs. 
 
 Let us take, in imagination, a trip on an " up " 
 escalator. The first thing we notice is a substantial 
 barrier somewhat like a shop counter. From beneath 
 a strip of what looks like floor is continually moving, 
 and on to this " floor " we step. It is moving 
 sufficiently slowly for us to do this with ease. 
 
 If we look carefully at this piece of moving floor 
 
 oojy 
 
 Fig. 19. DIAGRAM SHOWING HOW AN ESCALATOR WORKS, 
 
 Each step is a small trolley on four wheels. There are four 
 rails. The lower wheels run on the inner rails, the upper ones 
 on the outer. 
 
 we notice that it consists of long, narrow strips 
 fitting closely together, and as it approaches the 
 stairs the leading strip suddenly commences to rise 
 and so forms itself into a step. Strip after strip 
 thus rises in succession, including the one we are 
 standing on, with the result that we are carried 
 upwards upon it. 
 
 On arrival at the top our step ceases to rise, but 
 instead moves along horizontally close behind the 
 preceding one, so that once again we find ourselves 
 
 251 
 
WONDERS OF THE UNDERGROUND 
 
 standing upon a moving floor, off which we step. 
 This moving floor, like that at the bottom, ends 
 underneath a strong barrier, and this is set at an 
 incline, so that if we failed to get off we would be 
 gently pushed off. 
 
 As we rise we probably lean against the handrail 
 at the side of the staircase, and if we are observant 
 we shall realize that that, too, is moving at just the 
 same speed as the stairs. It consists of a strong 
 band of leather, or some similar material, driven by 
 the same mechanism as the stairs. 
 
 This appears on the surface to be very wonderful, 
 but mechanically it is very simple, since the stairs 
 are simply a train of little four-wheeled trolleys, 
 closely coupled together, passing round a drum at 
 each end. 
 
 The front wheels and the back wheels are not 
 quite the same distance apart, so that they run on 
 four rails, not on two. The front pair of wheels 
 (going up) run on the outer rails and the rear pair on 
 the inner rails. 
 
 On the sloping part of the stairway all four rails 
 are upon the same level, so that in that part of its 
 journey each step travels just like any ordinary 
 four-wheeled trolley. 
 
 At the top and the bottom the rails, of course, 
 turn into a horizontal plane so as to carry the steps 
 along horizontally, in order that they may form 
 that moving floor which enables us easily to step on 
 and off. If all the four rails, however, were to change 
 their direction at once, the steps would tip over, 
 so the outer ones rise higher than the inner before 
 
 252 
 
WONDERS OF THE UNDERGROUND 
 
 changing, just sufficiently to keep each step "on an 
 even keel," so to speak. Likewise, and for the same 
 reason, the inner rails change direction at the foot 
 of the stairs at a lower point than do the outer ones. 
 
 All this is rather difficult to explain in words, but 
 a glance at the diagram on page 251 will make it 
 quite clear. 
 
 But for this arrangement, of course, the steps 
 would tip up when they started to rise, a very un- 
 comfortable thing for the passengers, but arranged 
 thus the steps always keep their position and change 
 from flat floor to stairway quite simply and auto- 
 matically. 
 
 Another feature of the tubes which may be men- 
 tioned in conclusion is the supply of " ozone " to 
 keep the air fresh. Reference has been made else- 
 where to the earthy smell prevalent in some tubes, 
 and there is no doubt that, in some cases at all events, 
 the disappearance of this is largely due to the action 
 of " ozone." 
 
 As we all know, the great purifying agent in all 
 things is oxygen. If we want to clear away offensive 
 matter of any sort we burn it if possible, which 
 means that we rapidly oxidize it. If it is not possible 
 or convenient to burn it we smother it with some 
 substance which we call a disinfectant, the essential 
 feature of which is a plenteous supply of oxygen. 
 All disinfectants have plenty of oxygen in them in 
 such a state that it is easily disturbed, so that it 
 leaves the disinfectant and oxidizes the offensive 
 matter. This is precisely the same thing as burning, 
 except that it takes place more slowly. 
 
 253 
 
WONDERS OF THE UNDERGROUND 
 
 Now ozone is simply oxygen in an unstable form, 
 so that it is more ready to attack other things than 
 ordinary oxygen is. Like everything else, oxygen 
 consists of atoms, and ordinarily these atoms are 
 done up in bundles of two, but in ozone they are in 
 bundles of three. Now they do not tie up nicely in 
 threes ; one of the three is very apt to slip out, and 
 so wherever there is ozone there is likely to be a lot 
 of loose atoms of oxygen, under "which condition 
 they are very active and quickly combine with 
 anything else of a suitable kind that happens to be 
 at hand. 
 
 Ozone is usually supposed to be plentiful at the 
 seaside, and to it many watering-places owe their 
 invigorating properties. It can be made artificially 
 by means of an electric discharge, and this is how it 
 is provided for cleansing and purifying a tube tunnel. 
 At certain places the ozone apparatus is installed 
 and the ozone produced is fanned through suitable 
 ducts to convenient points, thereby giving to the 
 underground railway some of the properties of the 
 popular seaside resort. 
 
 254 
 
CHAPTER XIX 
 
 ELECTRIC TRAINS AND HOW THEY 
 ARE DRIVEN 
 
 THE steam locomotive has done grand service 
 to mankind in times past, and its career is by 
 no means at an end, but there can be no doubt 
 that for certain types of line dealing with certain 
 kinds of traffic the electrically propelled vehicle has 
 either displaced it already or will do so before long. 
 
 It is a mistake which is often made to speak of 
 electricity as if it were a source of power. It is 
 nothing of the kind. It merely transmits power 
 from a power house to the trains. It does not itself 
 drive a train any more than the familiar leather belt 
 connecting engine and machine in a factory itself 
 drives the machine. 
 
 In the steam-driven train the engine is a self- 
 contained unit. It carries its own coal and water with 
 it, and only needs a pair of rails to run on. Given 
 those rails to run on it can go anywhere. It may be 
 a little costly to make, compared with an electric 
 motor, it may not start so readily as an electric motor, 
 it may be less efficient, but it needs the minimum 
 of expenditure on the track. 
 
 The electric vehicle, on the other hand, is cleaner, 
 handier, more easily driven, starts more quickly and 
 
 255 
 
ELECTRIC TRAINS -HOW DRIVEN 
 
 is more efficient, but it requires costly cables and 
 conductor rails and machinery for the transmission 
 of the power from the power house to the train. 
 
 These two sets of facts lead to the conclusion that 
 for lines where the trains are few and the journeys 
 long, the steam locomotive is likely to hold its own 
 for many years to come, but that for lines where the 
 trains are many and the journeys short the electric 
 train is pre-eminent. 
 
 The early electric railways were modelled on the 
 street railway or electric tram. The motors are 
 driven by current having a force of 500 volts, which 
 had become the recognized practice for tramways, 
 and the current is of the kind called direct. 
 
 That brings us to a point which it would be well 
 to explain forthwith. There are two kinds of electric 
 current. In one the electricity flows steadily and 
 continuously, always in the same direction. This is 
 spoken of as continuous current or direct current, 
 or more briefly as D.C. 
 
 In the other kind the electricity surges to and fro, 
 first one way and then the other. This kind of 
 current is called " alternating," or briefly A.C. It 
 will be noticed that A.C. has a property which D.C. 
 has not, namely, " periodicity," by which is meant 
 the rate at which the alternations take place. This 
 is generally fifty per second, but in some cases less 
 and in some more. It all depends upon the con- 
 struction and speed of the dynamo, so that by making 
 the dynamo in a certain way and driving it at a 
 certain speed any desired periodicity can be ob- 
 tained. 
 
 256 
 
 
ELECTRIC TRAINS -HOW DRIVEN 
 
 The term " cycle " is often used in this connection 
 and should perhaps be explained. A " cycle " of 
 operations is, of course, a series of actions performed 
 over and over again in the same order. In this case 
 current commences to flow in a certain direction, 
 it grows until it reaches a maximum, then declines 
 and finally fades away altogether, then it commences 
 to flow in the opposite direction, again attains a 
 maximum, after which it dies away once more. That 
 is the cycle, and the number of cycles per second 
 is the periodicity. So you may read that a certain 
 current is alternating and has a periodicity of so 
 many, or it may be described as simply " alternating 
 current, fifty cycles," or whatever the number 
 may be. 
 
 In the case of D.C., just as the current is steady 
 so is the pressure or " voltage " steady. In A.C., 
 on the other hand, the voltage varies just as the 
 current does. If B.C., therefore, is said to be 250 
 volts, for example, it remains steadily at about that 
 pressure all the time. If the same is said of A.C., 
 however, it means that that is an average pressure, 
 and that sometimes it is much higher. This has to 
 be borne in mind when matters of insulation are 
 under consideration. 
 
 This preliminary explanation is necessary in order 
 to lead up to the fact that there are two distinct 
 types of electrically propelled railway. The first is 
 worked by direct current, and of this the Underground 
 Electric Railways of London may be taken as a 
 great example. In the other type alternating current 
 transmits the power to the trains, and of this what is 
 
 R 257 
 
ELECTRIC TRAINS -HOW DRIVEN 
 
 called the " Overhead Electric " line of the London 
 and Brighton and South Coast Railway, serving 
 some of the southern suburbs of London, may be 
 taken as typical. 
 
 It may seem at first sight that since both are 
 electric they must be similar, but, in fact, they are 
 very different. The motors are different, the methods 
 of carrying the power to the train are different, and 
 the fitting up of the trains themselves is different. 
 It will therefore be necessary to describe them 
 separately. 
 
 We will commence with the D.C. kind. The 
 starting point is the generating station, where the 
 power is obtained from fuel of some sort, or from 
 falling water, if that is available. 
 
 Here are a number of generators or dynamos, 
 each driven by an engine or a steam turbine or a 
 water turbine. Whatever the source of power may 
 be it is employed in the most economical manner. 
 One of the reasons for the economy of the electrical 
 system as compared with the steam is that in a well- 
 equipped generating station the fuel can be burned 
 to much better advantage than is possible in an 
 engine w r hich has to be run with the train. 
 
 It is possible to reckon that quantity of work 
 which is the precise equivalent of the heat from the 
 fuel. By burning a sample of the latter the number 
 of heat units per pound of coal can be ascertained, 
 and each unit under ideal conditions would do work 
 equal to raising 773 Ibs. a foot high, or 773 foot- 
 pounds. 
 
 Unfortunately, in the conditions under which we 
 
ELECTRIC TRAINS HOW DRIVEN 
 
 live, this result is quite impossible, but this figure 
 furnishes us with a standard by which we can com- 
 pare the " efficiency " of power plants of various 
 kinds. If, for instance, it is found that 77 foot-pounds 
 of work are done for every heat unit in the fuel 
 burnt, then that plant is said to have an efficiency of 
 ten per cent. 
 
 Now if the efficiency of a steam locomotive were 
 five per cent it would be extremely good. Many are 
 far less than that, whereas in a power house the 
 efficiency would run into possibly the twenties. 
 
 In some power stations internal-combustion engines 
 are used, because with them a higher efficiency is 
 possible than with any form of steam engine. They 
 suffer, however, from certain defects, the result of 
 which is that in the largest stations steam is mostly 
 to be found, more especially steam turbines. In the 
 steam-driven power house much of the work is 
 automatic. At the great generating station of the 
 London Underground Railways at Chelsea the 
 boilers are on the upper floors of the boiler house. 
 The coal, having been elevated mechanically to the 
 level of the roof, runs along a conveyor right up in 
 the apex of the roof, whence it is thrown off, again 
 automatically, into bunkers. From these it falls 
 into the mechanical stokers, which continually feed 
 it into the furnaces of the boilers. The ash, in like 
 manner, falls down shoots to a lower floor, whence 
 it is carried out by mechanical means. 
 
 For the sake of economy several devices are 
 employed in the stationary power house which are 
 quite impossible, or only partly possible, on the 
 
 259 
 
ELECTRIC TRAINS -HOW DRIVEN 
 
 locomotive. For one thing, the heat which would 
 otherwise escape up the chimney is made to pass 
 through ranges of pipes, forming what are called 
 " super-heaters," whereby some of it is captured and 
 used to raise the temperature of the steam. Later 
 on more heat is extracted from the waste gases on 
 their way to the chimney by ranges of pipes called 
 " economisers," in which heat that would otherwise 
 be wasted is used to heat the water on its way to the 
 boilers. 
 
 The engines, too, whether turbine or reciprocating, 
 are fitted with " condensers," cool chambers into 
 which the steam passes after leaving the engine. In 
 the condensers the steam, being cooled, collapses 
 into water, so that inside the condenser there is 
 always a fairly good vacuum, and the suction of the 
 vacuum pulling upon the engine is added to the 
 pressure of the steam pushing at the other side. 
 
 The keeping cool of the condensers is quite a big 
 business at a large plant, necessitating vast quantities 
 of cold water. If a large river or lake be handy, 
 this is simply a question of pumping, but otherwise 
 some kind of cooling scheme is needed. At some 
 stations they carry the heated water to the top of a 
 huge tower and let it fall, like rain, the contact with 
 the air causing it to cool rapidly. In other places it 
 is sprayed upwards in a very fine spray with the same 
 result. 
 
 All these devices, super-heaters, economizers, con- 
 densers, cooling devices and the rest are all intended 
 for one purpose, namely, to obtain the best possible 
 result in work from the heat derived from the fuel. 
 
 260 
 
ELECTRIC TRAINS -HOW DRIVEN 
 
 These waste-saving appliances are, of course, 
 impossible to any considerable extent on the loco- 
 motive. 
 
 As a rule, each generator has a separate engine 
 or turbine to drive it, so that the two form a unit. 
 The current from each unit is led by cables to the 
 switch board, a large structure for holding the 
 switches and measuring instruments, by means of 
 which the flow of current is controlled. 
 
 Behind the " board " there are usually a number of 
 horizontal bars of copper, called " bus bars," to 
 which the current from all the generators is led and 
 from which all the outgoing cables draw the current, 
 which they lead away to the distant parts of the 
 line. 
 
 From the very nature of a railway it follows that, 
 no matter how nearly central the power station may 
 be, some of the current will have to travel a great 
 distance ; in other words, long cables will be required 
 to carry it to distant parts of the line. Practically, 
 the only material for these is copper, and copper is 
 expensive. Hence it is of the utmost importance 
 that these cables should be as thin as possible, or 
 the cost in copper will be enormous. 
 
 Let us take an example. If we think for a moment 
 of the problem of sending power by water through a 
 pipe we can see that it is equally possible to achieve 
 our end by sending a lot of water through, with only 
 a little force behind it, or a little water with a lot 
 of force. The chief difference between the two is 
 that the former requires a much bigger pipe than the 
 latter. 
 
 261 
 
ELECTRIC TRAINS -HOW DRIVEN 
 
 Although we cannot picture it to ourselves so 
 easily the transmission of power by electricity is 
 very similar. To attain a given result the less 
 pressure we use the more current do we need, and the 
 larger the cables necessary to carry it. On the 
 other hand, by using a high pressure we can reduce 
 the quantity of current and so bring down the expense 
 for copper to a minimum. 
 
 It is therefore an invariable rule that the generators 
 in the central power house are so constructed as to 
 give out a comparatively small current at a very 
 high pressure, or, to use the more frequent term, 
 " tension." 
 
 This pressure or tension is that quantity which 
 is expressed in " volts." The current for the Under- 
 ground is generated at 11,000 volts. 
 
 All mechanically generated current is of the 
 alternating variety. A few attempts have been made 
 to devise machines to generate direct current, but 
 none has been satisfactory. In order to obtain 
 direct current, therefore, the generator has to be 
 fitted with a part called a commutator, a mechanical 
 device, the effect of which is to change the direction 
 of the current passing through it at frequent in- 
 tervals. The effect of this is to neutralize the original 
 alternations. It is as if the commutator took one- 
 half of each cycle and reversed it, thereby changing 
 the alternating current into direct. 
 
 Now this device does not act nicely when the 
 voltage is high, so that the high-tension currents 
 which leave the central station to carry the power 
 far and wide are always generated by alternating 
 
 262 
 
ELECTRIC TRAINS -HOW DRIVEN 
 
 current generators, or, as they are more frequently 
 termed, alternators. 
 
 So the high-tension alternating current sets out 
 upon its journey. Dotted about the railway system 
 are smaller stations, known as sub-stations, where 
 the current is transformed and converted in order 
 to make it suitable for driving the motors on the 
 trains. 
 
 The use of these two terms is quite arbitrary. So 
 far as their real meaning is concerned either of them 
 could be used instead of the other, but it is the 
 custom to speak of transforming the current from 
 high tension to low and converting it from alternating 
 to direct. 
 
 The transformers in the sub-stations are in prin- 
 ciple precisely like the induction coils with which 
 most of us have at some time or other tried to shock 
 people. Of course, they are much larger, but like 
 the induction coil they consist of two coils of insulated 
 wire. Through the first is passed the high-tension 
 current from the power station, and that, being 
 alternating, acts upon the other coil, and the two 
 are so arranged that the secondary current is some- 
 where about the 500 volts required by the motors. 
 
 It would be possible to use this transformed 
 current straight away ; but the direct current motor 
 is such a beautiful machine, it starts so nicely and 
 is so easily controlled that many engineers prefer to 
 convert this low-tension current into direct current 
 before sending it out to the conductor rails for use 
 by the trains. 
 
 Therefore the sub-station also contains, in addition 
 
 263 
 
ELECTRIC TRAINS HOW DRIVEN 
 
 to the transformers, machines called converters. 
 These are in appearance, and in construction, too, 
 very like generators, but they are not driven mechani- 
 cally. The alternating current which is fed into 
 them serves to drive them, and in passing through 
 them is changed into direct current by a commu- 
 tator, such as has already been described. 
 
 The total result is, then, that alternating current 
 at 11,000 volts or thereabouts goes into the sub- 
 station, while direct current at about 500 volts 
 comes out. 
 
 The cables or. "feeders" from the sub-stations 
 terminate at various points upon the conductor 
 rails, which are laid down by the side of the rails 
 upon which the trains run and from which the trains 
 pick up the current as they go. 
 
 Upon the trains themselves the only apparatus 
 necessary is one or more motors and a controller, 
 by means of which the driver can regulate the speed 
 and the direction of the trains. 
 
 The controller generally has two handles. One of 
 these determines the direction. An electric motor 
 consists of two sets of electro-magnets, which act 
 upon each other. If you change the direction of the 
 current in one of them you reverse the action. Hence 
 all that this handle has to do when it is turned is 
 to change the direction of the current through one 
 of the sets of magnets in the motors. This it does 
 in a very simple manner. There is inside the con- 
 troller a drum-shaped object carrying a number of 
 curved metal strips, carefully insulated from each 
 other and from the drum. On the frame of the 
 
 264 
 
ELECTRIC TRAINS -HOW DRIVEN 
 
 controller there are fingers of metal, which in certain 
 positions make contact with the strips. The handle 
 is attached to the end of the shaft upon which the 
 drum is fixed, and when it is moved it takes certain 
 strips out of contact and brings others into contact, 
 thus, in the simplest imaginable way, making 
 the necessary changes in the direction of the 
 current. 
 
 The other handle controls the speed. It likewise 
 is connected to a drum carrying strips, and as it is 
 turned it varies the connections with the corre- 
 sponding fingers. If a slow speed is required it 
 sends the current round through a lot of coils of 
 wire, the resistance of which diminishes the quantity 
 of current and so keeps the speed down. When it 
 is desired to increase the speed the controller cuts 
 out these resistance coils one by one until, at the 
 highest speed, the current is going straight to the 
 motors without the intervention of any resistance 
 at all. 
 
 Since the driver of an electric train is frequently 
 alone in his cabin and has no mate, as his colleague 
 of the steam train has, the controller handle is made, 
 when left alone, to spring back to the position where 
 it cuts off all current and stops the train. This 
 device, which is nicknamed by the men the " dead 
 man's handle," is intended as a safeguard against 
 the possibility of a driver fainting at his post and the 
 train running along out of control. 
 
 The brakes on an electric train are generally 
 worked by compressed air, in a similar manner 
 to those on many steam trains. There is a small 
 
 265 
 
ELECTRIC TRAINS HOW DRIVEN 
 
 subsidiary motor, the duty of which is to keep the 
 reservoir of compressed air filled. 
 
 Now let us turn our attention to the alternating 
 current systems and see how they differ from those 
 just described. 
 
 The power station is not materially different, but 
 of sub-stations there are none. Therein lies the 
 first difference. 
 
 The high-tension alternating current is fed straight 
 to the conductors from which the trains collect it. 
 Since the tension, or pressure, is so high, to touch 
 one of these conductors would mean instant death, 
 so a rail upon the ground, on to which an unwary 
 platelayer might step, is out of the question. In- 
 stead of a conductor rail, therefore, there is a heavy 
 copper wire, supported high in air out of everyone's 
 reach. Not only does it need to be high up, but the 
 insulation has to be exceedingly good, for otherwise 
 the current would leak to the posts. Moreover, 
 the conductor wire has to be very level, for if it rose 
 and fell to any great extent the collector on the top 
 of the train would not make a steady contact with it. 
 Long spans of wire, such as we see in the case of 
 tramways, are all right for the comparatively slow- 
 moving cars, but they would never do for the more 
 speedy train. 
 
 These two last difficulties, the insulation and the 
 level wire, are overcome by one and the same ar- 
 rangement. 
 
 Tall posts or light steel towers are erected by the 
 side of the line, generally in pairs with a light steel 
 girder spanning between them, like a bridge. To these 
 
 266 
 
ELECTRIC TRAINS -HOW DRIVEN 
 
 there are fixed two steel wires which, not being very 
 tightly stretched, form easy curves. Below these 
 wires and between them is stretched the conductor, 
 supported from them by short wires at frequent 
 intervals. By varying the length of these short 
 wires it is thus possible to keep the conductor prac- 
 tically straight. 
 
 One may wonder, perhaps, why the conductor 
 should not be pulled so tightly between its supports 
 that it would be practically level all along, but the 
 answer is that to do so would need such a tremendous 
 pull as almost, if not quite, to break it. This does 
 not happen, however, when the wire can be sup- 
 ported at frequent intervals as it is by the short 
 wires. 
 
 It may be asked, does not the same thing apply to 
 the two steel wires. It does, but they are not pulled 
 tight, being left fairly loose, since a considerable 
 sag in them does not matter. It is all taken up by 
 the variation in the length of the short wires. 
 
 The steel wires are carried on insulators fixed 
 upon the bridges. This is theoretically unnecessary, 
 because there ought to be no current in the steel 
 wires at all. This is so, because near the centre of 
 each of the short wires, or where it connects to the 
 long steel wires, there is inserted a porcelain insulator. 
 In other words, every short wire is itself insulated. 
 
 If everything were as it ought to be no current 
 should get to the steel wires, but should it by any 
 chance do so the other insulators, those mentioned 
 first, come into operation and prevent the current 
 from escaping further. 
 
 267 
 
ELECTRIC TRAINS -HOW DRIVEN 
 
 In fact, they act together, reinforcing each other 
 and so making the whole arrangement very safe. 
 
 On the top of each motor coach in the trains there 
 is a collector. It is rather different from the simple 
 arm with a wheel at the end, such as tramway cars 
 have, although the purpose is much the same. Here, 
 again, the difference is made necessary by the higher 
 speed of the train. 
 
 In this case the collector is usually a frame or 
 metal rectangle, one side of which is hinged to the 
 top of the coach, while the whole thing is raised up 
 so that the opposite side presses steadily upwards 
 against the underside of the conductor wire. In 
 practice it is desirable that the collector should trail 
 along rather than be pushed along in contact with 
 the wire, hence each motor coach has two, one each 
 way, and when the train reverses one goes out of 
 action, lies flat upon the roof so as to be out of 
 action, while the other one is raised and comes into 
 operation. The change is made quite easily by 
 compressed air worked from the driver's cabin. 
 
 On arrival upon the train the current is still at a 
 very high voltage, too high for practicable use on 
 the motors, so it is led to a transformer carried upon 
 the train which lowers the voltage, and the low-tension 
 current is then led to the motors. 
 
 One drawback, as will be noticed, to this system 
 is that it entails the constant hauling about of heavy 
 transformers. Another very obvious one is the 
 high cost of the structures for carrying the con- 
 ductors. 
 
 Which is really the better of the two is a matter of 
 268 
 
ELECTRIC TRAINS -HOW DRIVEN 
 
 much discussion. Like most questions, there is 
 much to be said on both sides, and it seems highly 
 probable that the next step will be a compromise 
 between the two ; that is to say, high-tension current, 
 transformed down by transformers dotted about the 
 system and fed to conductor rails upon the ground. 
 
 In some installations there are two separate con- 
 ductor rails, one positive and one negative, or in other 
 words, one along which current flows from the power 
 station and one along which it travels back again. 
 There are others, however, in which only one is 
 used, the track rails serving the purpose of the other. 
 
 It may be asked, " What is the good of the negative 
 or return rail ? Is it so that the electricity can be 
 used over again ? If it is not used, is the electricity 
 wasted ? " 
 
 The answer is that when heavy currents are let 
 loose, so to speak, in an uninsulated rail, they are 
 apt to stray about and cause corrosion of pipes and 
 other things buried in the ground by setting up the 
 action called " electrolysis." Consequently, where 
 the flow of current is likely to be heavy and there 
 are many pipes about the insulated return is generally 
 installed. Where the currents are not so heavy, 
 because there are fewer trains and the line runs 
 through more open country, the insulated return is 
 often dispensed with. 
 
 The question of wasting electricity does not really 
 arise at all, because the whole earth is saturated with 
 it, and consequently it is about the cheapest thing in 
 existence. It only becomes of value when force is 
 put into it. It is the force which costs money, and 
 
 269 
 
ELECTRIC TRAINS HOW DRIVEN 
 
 the force which makes an electric current valuable. 
 Now this force is used up in the motors. The very 
 essence of an electric motor is that it catches, so to 
 speak, the force in the current, extracts it and uses 
 it for some mechanical purpose, in this case to drive 
 the train. 
 
 That is the reason why there is no danger in using 
 the rails of a tramway in the public street for the 
 return current. By the time the current has been 
 through the motors all its force is gone, there is 
 barely enough left to ring an electric bell, and cer- 
 tainly not enough for anyone to feel. 
 
 So that is how electric trains are driven. No 
 attempt has been made to describe all the slight 
 differences which occur between different systems, 
 but enough has been said to give a general idea of 
 the broad principles underlying them all, and the 
 facts stated will enable anyone to understand generally 
 how they work. 
 
 270 
 
CHAPTER XX 
 A RAILWAY IN THE AIR 
 
 IF you sail in a ship across the Atlantic as if 
 you were going through the Panama Canal, but 
 instead of entering the canal turn to the left 
 and follow the coast for a while, you will come to a 
 large river called the Magdalena. 
 
 This rises in the Andes, flows down a broad valley 
 formed by two spurs of that great range, and serves 
 as an important highway for traffic. The country 
 through which it passes is the Republic of Colombia, 
 and one of the most important towns upon its banks 
 is called by the beautiful name of Mariquita. 
 
 Away to the westward of Mariquita is a stretch of 
 country of the most varied types. Parts of it are 
 tropical, with the luxuriant vegetation which usually 
 grows under those conditions. Other parts are rocky 
 and precipitous, as we might expect when we remem- 
 ber the nearness of the great Andes range. Some of 
 the higher valleys, again, are of great fertility, 
 sharing as they do many of the advantages of the 
 tropical sun, but escaping many of the disadvantages 
 because of their altitude. 
 
 Particularly is this the case with an area the centre 
 of which is the town of Manizales, about forty-five 
 miles to the westward of Mariquita. This district 
 
 271 
 
A RAILWAY IN THE AIR 
 
 produces bountiful crops of coffee and spices, but 
 unfortunately a range of high mountains with rugged 
 foot-hills intervenes between the two towns, so that 
 Manizales must be one of the most isolated places 
 for its size in the whole world. 
 
 Although it has a population of about 30,000 it 
 has no main road leading to anywhere. The longest 
 road out of it is only a few miles long and it leads to 
 nowhere, but simply ends by losing itself among the 
 rough country at the foot of the mountains. 
 
 Given a reasonably good path, there is many a 
 man who could walk the distance betw r een these two 
 towns in a day, but until a few years ago the only 
 communication between the two was a mule journey 
 of about three days in summer and possibly nine or 
 ten in the winter. 
 
 Not only was much time thus lost, but much 
 valuable merchandise was spoilt by damp and heat 
 experienced during the trip. In short, the whole of 
 this district, rich in its crops, round Manizales, was 
 rendered poor because it had no satisfactory outlet 
 through which it could exchange its wealth with 
 other people. 
 
 At Mariquita there is a railway, owned by an 
 English company, called the Dorada Railway Com- 
 pany, who had for years looked towards Manizales 
 and coveted the valuable traffic which was waiting 
 to be carried, if only they could devise a practicable 
 way. 
 
 The nature of the country, however, put an 
 ordinary railway quite out of the question. To 
 commence with, the steepness of the gradients would 
 
 272 
 

A RAILWAY IN THE Affi 
 
 be far too great. The town of Mariquita is only 
 1500 ft. above the sea, but Manizales is about 7000, 
 and between them is the mountain range, at least 
 12,000 ft. high. In addition to this the roughness 
 of the country in parts would necessitate such a 
 series of bridges and tunnels and cuttings and via- 
 ducts that the cost would be prohibitive. No amount 
 of traffic could ever pay a dividend upon it. 
 
 All these difficulties, however, vanish, or at any 
 rate are greatly reduced, if the railway can be lifted 
 off the ground and carried through the air, which is 
 practically what has been done. A rope railway, or 
 ropeway, has been installed, whereby the loads of 
 goods are carried easily and economically over the 
 wildest mountainous country. 
 
 It is not suggested that the idea of a ropeway was 
 invented for this particular work. The principle is 
 much older than that and there are many such 
 things about, but this was the first time on which 
 it had been used on so large a scale and as a definite 
 extension of a railway. This is emphasized by the 
 fact that a new company was formed in London, 
 called the Dorada Railway Ropeway Extension 
 Company, Limited, to carry it through. 
 
 The earliest ropeways consisted of two ropes, 
 parallel with each other, securely held at each end, 
 along which little trolleys were hauled by means of 
 a third, endless, rope to which the trolleys were 
 attached. Buckets or some other convenient form 
 of receptacle were hung beneath each trolley, and 
 there was an arrangement whereby the trolleys on 
 reaching their destination could be detached from 
 s 273 
 
A RAILWAY IN THE AIR 
 
 the " hauling rope " and run on to a sort of siding or 
 " shunt rail," as it is termed, to be unloaded. 
 
 If the length of the ropeway is very short the 
 " track ropes " need only to be strongly held at each 
 end, but in the great majority of cases intermediate 
 supports are required in the form of towers or trestles. 
 Each trestle has two projecting arms near its top, 
 so that it may be likened to a man of gigantic pro- 
 portions standing between the ropes with outstretched 
 arms, supporting one rope in each hand. The track 
 ropes are so attached to these " arms " that the 
 wheels of the trolleys can run easily past them. 
 
 The heights of the trestles vary according to cir- 
 cumstances. In some cases they only need to be just 
 high enough to allow the buckets to clear the ground. 
 Such an instance would occur at the top of a hill. 
 At the bottom of a deep valley, however, if the 
 trestle were equally short, the ropes might be far 
 too steep, and to mitigate this the trestle would be 
 made considerably higher. 
 
 The kind of ropeway just described is known as a 
 double rope or bi-cable line, and under certain con- 
 ditions they are to be preferred to any other. The kind 
 adopted for the Dorada Ropeway is a newer type in 
 which one cable does everything, and which is, there- 
 fore, called a mono-cable, or single rope line. 
 
 Imagine a long rope of steel with its ends spliced 
 together so that it is endless, looped round two 
 large grooved wheels about 8 ft. in diameter, the two 
 wheels being several miles apart. The two halves of 
 the rope will be parallel, separated by a distance of 
 8 ft., and if the two wheels be turned round one part 
 
 274 
 
A RAILWAY IN THE AIR 
 
 of the rope will travel in one direction and one part 
 in the other. 
 
 Further, imagine these 8-ft. wheels to be secured 
 to a suitable steel framework, so that the rope can 
 be stretched with any desired degree of tightness, 
 and finally picture a long row of trestles supporting 
 the rope at intervals and you will have a good mental 
 picture of this wonderful installation. 
 
 In this case, of course, the ropes are not fixed to 
 the trestles, but are simply supported by grooved 
 wheels carried upon the trestles, the wheels revolving 
 as the rope passes over them. 
 
 The buckets or other receptacles for goods are 
 attached to clips which hook over the rope, being 
 so shaped that they can pass over the grooved wheels 
 on the trestles without being thrown off the 
 rope. 
 
 Herein lay one of the chief difficulties in the use of 
 a single rope, for at first it was thought impossible 
 to devise a form of clip which would be able on the 
 one hand to grip the rope firmly enough not to slip 
 on an incline, and on the other capable of passing 
 over the wheels. After much experimenting the 
 problem was solved by Mr. J. P. Roe, an engineer 
 who specialized for years in ropeway matters and 
 who was largely interested in the Dorada Ropeway. 
 He found that if he made a simple hook-shaped 
 clip to go over the rope, with a single small pro- 
 jection upon it of such a shape that it lay in between 
 the strands of the rope, no slip would take place on 
 all reasonable inclines. The elaborate and costly 
 mechanical forms of grip which had previously been 
 
 375 
 
A RAILWAY IN THE AIR 
 
 thought essential and which presented all manner 
 of difficulties were found to be quite unnecessary. 
 
 It may be said without exaggeration that this kind 
 of ropeway, with its many advantages over the older 
 type, was only made possible by this beautifully 
 simple invention. 
 
 But perhaps some readers may wonder why this 
 difficulty does not arise equally in those cases where 
 the thing is hauled along by a separate rope, for the 
 trolleys must of necessity be detached from the 
 hauling rope in that case also. The answer is that 
 the hauling rope in a bi-cable system does not need 
 to pass closely through the groove upon the edge of 
 a revolving wheel. 
 
 The large wheels around which the rope passes at 
 each end are mounted in specially constructed steel 
 frames. That at one end, called the driving end, 
 has a tooth wheel coupled to it by means of which 
 it is driven round, the power being derived from a 
 steam engine or other form of motor. 
 
 At the other end, the " tension " end, the wheel 
 is mounted upon a small trolley which runs upon 
 rails embodied in the frame, and is pulled back by 
 means of a heavy weight, thus ensuring that the 
 correct tension shall be kept upon the main rope. 
 
 A loaded bucket, upon arrival at its destination, 
 is, by beautifully simple means, shunted off the rope 
 on to a " shunt rail," which is mounted upon the 
 top of the station frame. The rope comes into the 
 station at a certain angle ; there it passes over a 
 pulley, after which it takes a slightly downward 
 direction to the large wheel, which is set at the 
 
 276 
 
A RAILWAY IN THE AIR 
 
 correct angle to receive it. Having passed round 
 the large wheel it comes upward once more, passes 
 over another wheel and goes out slightly downwards. 
 
 Fig. 20. DIAGRAM SHOWING HOW THE RAIL LIFTS THE 
 
 LOAD OFF THE ROPE. 
 (Details much altered, for simplicity.) 
 
 As the rope descends, at the station, the roller engages with 
 the rail which supports the whole thing, while the rope with- 
 draws itself from the clip. 
 
 The shunt rail is practically horizontal, one end 
 being near the first wheel just mentioned and the 
 other end near the one last mentioned. Further, 
 each clip has connected with it two small grooved 
 
 277 
 
A RAILWAY IN THE AIR 
 
 rollers which, when the thing is on the rope, do 
 nothing. 
 
 The bucket, then, comes sailing in, so to speak. 
 After passing the first wheel the rope changes its 
 direction downwards, thereby dropping the two 
 rollers on to the shunt rail. The rollers thus take 
 the weight of the bucket, lift it off the rope, as the 
 latter moves downwards, and leave it free to be run 
 along the shunt rail to the desired position for un- 
 loading. After being unloaded the bucket is pushed 
 along the shunt rail until the process is reversed ; 
 the rope coming upwards gets under the clip, lifts 
 the rollers off the rail and carries the bucket away. 
 
 What has been said up to the present is little more 
 than a description of ropeways in general. It was 
 necessary in order to make intelligible the account 
 of the marvellous installation, which really forms 
 the subject of this chapter. 
 
 The total length of this, as has been said, is about 
 forty-five miles, but it must not be thought that the 
 ropes run continuously for that distance. It is 
 divided up into sixteen sections. It might thus be 
 said to be sixteen ropeways placed end to end. 
 They are not really separate, however, because at 
 the intermediate stations the shunt rails are so 
 arranged that a bucket coming in from one section is 
 passed on to the next section instead of being sent 
 back, as would be the usual arrangement. 
 
 The division of the line into sections also has the 
 advantage of enabling it to follow a more or less zig- 
 zag route, thereby serving a number of intermediate 
 villages, for, of course, each section has to be straight, 
 
 278 
 
A RAILWAY IN THE AIR 
 
 for otherwise the rope would never lie comfortably 
 in the wheels which support it. The longest of the 
 sections is 5800 metres, and the shortest 2590. The 
 former rises 240 metres, but the latter, although so 
 much shorter, rises nearly 400 metres, and it is this 
 steep gradient which necessitates the section being- 
 short, because if it were longer the pull of a large 
 number of buckets would be too much for the rope. 
 
 Fig. 21, 
 
 This diagram shows how the loads are passed from one section 
 of ropeway to the next. 
 
 On arrival at A, the rope dips downwards, leaving the load 
 supported by its rollers upon the shunt rail. The load is pushed 
 along the rail to B, where the opposite occurs, the rising rope 
 engaging in the clip lifting the load off the rail and carrying it 
 away. At the end station the shunt rail curves round some- 
 what as shown dotted. 
 
 The stations are arranged alternately, so that 
 with one exception two driving stations always come 
 together and two tension stations, thereby keeping 
 the number of points where power is required down 
 to the minimum. 
 
 The power is derived from steam engines, of which 
 a number each of 30 horse-power were sent out from 
 England. Where 30 horse-power is not enough two 
 engines are employed. The boilers are made with 
 
 279 
 
A RAILWAY IN THE AIR 
 
 specially large fire-boxes, so that wood fuel, which is 
 plentiful in the neighbourhood, can be used. Engines 
 and boilers alike were specially designed so that they 
 could be taken to pieces for transport, and no single 
 piece weighed more than 10 cwt., the great bulk of 
 the material being actually packed in cases of not 
 more than 2 cwt. 
 
 This was necessary because of the system adopted 
 throughout of making a finished section carry the 
 material for the next one, and the further need 
 of transporting over intermediate distances by 
 mules. 
 
 The rope itself weighed the astonishing amount of 
 255 tons. It has a circumference of 2f ins., and is 
 constructed of steel wires, having a breaking strain 
 of 105 tons per square inch. The actual rope has a 
 less degree of strength than that, because, of course, 
 it is not solid wire, but has a number of spaces in 
 between. The load necessary to break the rope is 
 just over 30 tons. 
 
 It is, of course, impossible to divide the rope up 
 into small pieces for transport, as was done with the 
 engine and other parts, for that would mean too 
 many splices. The same result is attained, however, 
 by making it into small coils with a length of loose 
 rope between. The coils are then tied in pairs and 
 slung one each side of a mule, the intervening lengths 
 of straight rope stretching from mule to mule. The 
 animals are thus tied together, much after the fashion 
 of alpine climbers, and many anxious moments there 
 were when one mule in a long train showed a ten- 
 dency to slip on a mountain track, for if he had gone 
 
 280 
 
A RAILWAY IN THE AIR 
 
 the whole train might have followed him, together 
 with some tons of rope, down the mountain side. 
 
 The trestles number 437, some as low as 3 metres, 
 but one, at least, reaching 66 metres, about five times 
 the height of an ordinary three-storey house. 
 
 All the smaller ones were of a kind specially 
 developed by Messrs. Ropeways, Limited, the con- 
 tractors for the line, in which a lot of small pieces 
 are sent out in bundles and put together on the spot, 
 much as boys build things with " meccano." They 
 are tripod arrangements, the three legs being joined 
 together at intervals by horizontal struts, and then 
 the whole tied together with diagonal rods, which 
 can be tightened up by screwing them round. 
 
 Where a very tall trestle was needed a special base 
 was designed, and then one of these standard ones 
 put on the top of it. 
 
 In other cases, where the load upon a trestle is 
 very heavy a stronger kind of structure, with four 
 legs, was used instead of these. 
 
 At each trestle a pair of stout steel beams are 
 fixed projecting out horizontally on either side, to 
 carry the " sheaves." Where only one single sheave 
 is required the spindle upon which it turns is fixed 
 to the end of this beam, but such cases are not 
 frequent. The pressure of the rope is generally too 
 great to be taken safely by one sheave, so that two, 
 four and in some cases eight are used. But it would 
 clearly be no use to increase the number of the 
 sheaves unless it could be made sure that each one 
 would take its fair share of the load, but that diffi- 
 culty is overcome in a very interesting way. 
 
 281 
 
A RAILWAY IN THE AIR 
 
 Let us take first of all a pair. In this case, a short 
 beam is pivoted on the end of the main beam, and one 
 sheave is placed at each end. Thus the " pair beam," 
 as it is termed, can see-saw, and whatever the pres- 
 sure on the rope may be and at whatever angle it 
 may pull, each sheave takes exactly half. If there 
 be four sheaves a larger beam is balanced upon the 
 end of the main beam, this one being termed a 
 " quad beam," carrying at each end a pair beam 
 with its two sheaves. Thus the pair beams see-saw 
 
 Fig. 22. How THE ROPES ABE SUPPORTED WHERE THE 
 
 LOADS ARE VERY HEAVY. 
 
 Eight wheels are used, and seven beams. One beam is 
 supported upon the trestle at A. This in turn supports two 
 others at B. These, again, carry four others at C, and these 
 carry the wheels. 
 
 All the beams are free to rock upon their centres, with the 
 result that all the wheels are ''alive," and each has to do 
 exactly its fair share of the work. 
 
 upon the ends of the quad beams and the quad 
 beam upon the end of the main beam. 
 
 The same principle prevails when the sheaves 
 number eight, an " octo " beam being first supported 
 upon the end of the main beam, two quad beams 
 upon that, and four pair beams upon them, eight 
 sheaves completing the whole series. The result of 
 all this is that, whatever the load may be, all the 
 sheaves get their fair share and no more. 
 
 Normally the limit for each load is 6 cwt., but by 
 special arrangement as much as 10 cwt. can be 
 
 282 
 
A RAILWAY IN THE AIR 
 
 carried. The speed of the line is 120 metres per 
 minute, or four and a half miles per hour, and the 
 loads follow each other at the rate of about one 
 every two minutes. 
 
 The vehicles, as one might call them, in which the 
 goods are carried are of various kinds, according to 
 what has to be carried. For some things buckets 
 are used, for others a kind of wooden platform with 
 an iron sling is found most convenient, while for 
 long articles a pair of carriers some distance apart, 
 but coupled together with a flexible connection, are 
 used. 
 
 The operation of the line soon had its effect upon 
 the commerce of the district, the amount of coffee 
 exported, to give only one instance, increasing in a 
 few years from 9000 to 18,000 tons. As time goes on 
 this will no doubt increase, until the line will be 
 working at its full capacity of 20 tons per hour in 
 the downward direction, towards Mariquita, and 
 10 tons per hour the other way. 
 
 283 
 
CHAPTER XXI 
 FIGHTING NATURE IN CANADA 
 
 IN a previous chapter we had a brief review of the 
 difficulties encountered in surveying for and 
 plotting out the course of the Grand Trunk 
 Pacific Railway. Now we will look at some of the 
 tasks which confronted the men who actually con- 
 structed the line. 
 
 Naturally, in a line of such length, there were 
 many varieties of country to be crossed. For a 
 part of its length the country was flat prairie, where 
 little had to be done except lay the rails. The 
 ground was already flat and firm. 
 
 In other places, however, the difficulties were such 
 as to make up, many times over, for the ease of 
 working upon the prairie. There were dense forests 
 to be cut through, swamps to be crossed, bridges 
 to be built, and in some spots rock was encountered 
 in a particularly annoying form. 
 
 It was just as if huge pieces of rock had been 
 flung about promiscuously by giants at play. The 
 rocks were too rough and detached to form the bed 
 of the line, they were too close for the line to pass 
 between, and the only thing was to hew a way 
 through them. 
 
 The work was, of course, started at the two ends, 
 
 284 
 
FIGHTING NATURE IN CANADA 
 
 and in addition it was attacked at several intermediate 
 points where transport was possible. Several lakes 
 and convenient water-ways materially assisted in this. 
 
 The most convenient way to work is obviously 
 from an end, because as the line proceeds the 
 materials, tools and men can be brought along it 
 to the rail-head. Every yard that is made becomes 
 a tool for use in making the next yard. 
 
 On a long line, however, the work would progress 
 but slowly if it were carried on only from the two 
 ends. Yet if it be through wild country it may be 
 exceedingly difficult to get the necessary men and 
 material to any intermediate point. Consequently, 
 a friendly water-way, even if it be somewhat incon- 
 venient, may be a welcome help if it gives access 
 to an intermediate point. No doubt this matter was 
 given due consideration when deciding upon the 
 precise course of the line. 
 
 The task confronting the engineers was to form, by 
 some means or other, a smooth level track 100 ft. 
 wide and about 3500 miles long, so that the need 
 for intermediate starting points is evident. 
 
 Let us take first the forest country. Here the 
 trees were felled and the undergrowth cut away by 
 armies of men with axes and similar tools. The debris 
 was piled in the centre of the track and burnt in huge 
 bonfires. At least, that happened to all such as was 
 not required for use in the construction operations. 
 Great care was, of course, taken not to do this burn- 
 ing when the conditions favoured forest fires, and 
 every precaution was observed to see that damage 
 was not done. 
 
 285 
 
FIGHTING NATURE IN CANADA 
 
 As the track was thus cleared, camps were formed 
 for the accommodation of the men, and narrow- 
 gauge lines were laid down temporarily to carry 
 materials. These narrow-gauge lines were followed 
 in due course by other lines, temporary also, but of 
 the standard gauge. 
 
 After having been cleared of vegetation, the ground 
 had to be levelled ; humps had to be cut away and 
 hollows filled up, and in this all manner of mechanical 
 aids were employed to supplement the work of 
 men's hands. Of these may be mentioned the 
 " grading machine." 
 
 This is something like a plough in its action in 
 that it has a knife which, when the machine is pulled 
 along, cuts into the earth. It is drawn by many 
 horses, perhaps a dozen, in three rows of four, hauling 
 it from the front, while as many push it from behind. 
 As the knife scoops up the earth a small chain with 
 buckets attached is moved along, lifting the spoil 
 automatically and dropping it into the attendant 
 carts. 
 
 This machine can only be used where the earth is 
 fairly soft, but in such cases it is such a saver of human 
 labour as to be very valuable indeed. 
 
 What is done with the " spoil " depends upon 
 circumstances. If there are hollows to be filled in 
 it is used for that. If embankments require to be 
 made it may be hauled for miles along the temporary 
 lines for that purpose, but if no use presents itself 
 it is tipped into a ravine, or otherwise got rid of in 
 the easiest possible way. 
 
 In many parts of the line swamps were encountered, 
 
 286 
 
 I 
 
FIGHTING NATURE IN CANADA 
 
 or places known by the local name of muskeg. This 
 latter term means apparently something between a 
 swamp and dry land, land which is nearly dry, but 
 which is so soft that it cannot support a heavy 
 weight. A horse, were it to cross a muskeg, would 
 find its feet sinking in, and, of course, a railroad 
 would be far too heavy a load for it to support. 
 
 The muskegs were crossed by means of the roads 
 called, in that part of the world, " corduroy." These 
 consist of rough logs of wood laid down together, 
 parallel and in close contact ; presumably it is the 
 resemblance of such a road to the familiar fabric 
 called " corduroy " which has given rise to the 
 term. 
 
 Anyway, these logs so spread the weight of a 
 passing man or vehicle that passengers and carts 
 can freely travel over the muskeg on corduroy roads. 
 They will not carry a railway, however, so to make 
 the permanent road other logs are laid on the first 
 layer, at right angles, and to these are added brush- 
 wood and branches until a thick " mattress " is 
 formed several feet thick. Upon this earth is laid, 
 the weight of which causes the mattress to be pressed 
 into the soft ground, until at last a condition is 
 reached when added weight causes no further sinking. 
 Then the ground is firm and strong enough for the 
 railway to be laid. 
 
 It is rather interesting to remember that this form 
 of construction over soft ground may fairly be 
 attributed to the original George Stephenson, for 
 that is just how he carried the Manchester and 
 Liverpool line over Chat Moss, near Manchester. 
 
 287 
 
FIGHTING NATURE IN CANADA 
 
 In the case of swamps, which are much softer 
 and more wet, a more primitive method is employed. 
 The swamp is simply treated as if it were not there, 
 or rather as if it were an empty hollow. The line is 
 brought to the edge and earth is tipped in. At first 
 this sinks, and it seems as if all were labour in vain, 
 but after a time, a very long time in some cases, the 
 earth ceases to sink in, which is a sign that at last 
 an embankment is beginning to form upon the hard 
 bottom of the swamp. Then the line is carried for- 
 ward a little on to the firm ground thus formed and 
 more earth is tipped so that the embankment shall 
 be elongated, until at last it has been carried right 
 across the swamp. 
 
 And yet another way was employed in some cases 
 upon this wonderful line. Trees were cut down and 
 driven in like stakes into the bed of the swamp. 
 The tops of these being joined together by other 
 logs, eventually formed a light and somewhat flimsy 
 gangway across the swamp, over which the light 
 narrow-gauge line could be carried. Then day by 
 day trucks poured along this structure, each de- 
 positing its load of earth until the whole gangway 
 itself had become buried in a solid bank of earth. 
 This is a particularly quick and effective way for 
 forming an embankment across a swamp. 
 
 As has been remarked already, the country 
 traversed by this line is in parts cut up by small 
 rivers and ravines all running at right angles to the 
 line of route. This is particularly annoying, because 
 it necessitates a large number of small bridges, and if 
 the engineers had waited to build one bridge at a 
 
 288 
 
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FIGHTING NATURE IN CANADA 
 
 time there would have been great delay. On the 
 other hand, how could the material be got across for 
 the second bridge until the first had been made, and 
 in like manner, how could the third be constructed 
 until the second had been finished ? 
 
 The only thing to do was to utilize the timber 
 which was so plentiful and run up rough, temporary 
 bridges of timber to carry the temporary line, pending 
 the completion of the permanent bridges. This 
 enabled a number of the latter to be got on with 
 simultaneously. 
 
 A curious trouble was encountered in some parts 
 of the line. An embankment would be completely 
 finished and apparently as sound as a bell, when 
 suddenly a short length of it, perhaps a hundred feet 
 or so, would sink several feet. It was as if a weak 
 place developed in the solid earth and allowed the 
 embankment to sink in. As .a rule, it was only 
 necessary to add more earth at the top of the em- 
 bankment so as to bring the top up to the correct 
 level once more. 
 
 The rocky country, needless to say, had to be 
 dealt with on a different manner. Dynamite was the 
 king of this portion of the work. Men were collected 
 from all parts who were skilled in the use and handling 
 of this valuable aid to the engineer. The air was 
 filled with the sound of hammers striking upon the 
 drills with which the holes were made in the rock, 
 while at intervals the deep roar of an explosion would 
 roll over the wilderness. 
 
 At one spot a whole cliff had to be removed, and for 
 this purpose a shaft was sunk, almost like a well, 
 
 T 289 
 
FIGHTING NATURE IN CANADA 
 
 at the bottom of which was buried a charge of 
 dynamite of unprecedented size. The explosion 
 which followed in due course moved 30,000 tons of 
 rock. 
 
 Probably during the war far greater explosions 
 were brought about, but when this was done, just 
 before the war, it must have been almost a record. 
 
 One of the strange things about the use of explo- 
 sives is that the men get remarkably careless. The 
 science of explosives has been brought to such a 
 pitch that dynamite, properly handled, is perfectly 
 safe. It will only go off under certain well-known 
 conditions, and if these conditions be carefully 
 avoided, dynamite can be handled as safely as coal. 
 
 Thus the men get careless. They handle it so 
 often with safety that they eventually forget that 
 there is any danger in it at all, and then they oft- 
 times have to pay the extreme penalty. 
 
 Particularly is this the case during the winter when 
 the dynamite is apt to get frozen. In such condition 
 it is useless and has to be thawed, for which reason 
 the men frequently put it in front of a stove, or per- 
 haps on a stove or even in an oven. But after being 
 frozen and then thawed the dynamite is in a specially 
 sensitive state, far more so than usual, but the men 
 forget this and danger results. 
 
 It has been said, and it is a fine testimony to the 
 inherent goodness of even the roughest men, that 
 the only way by which the engineers can instil care 
 into the men who handle explosives is by appealing 
 to their care for others. The risk to themselves does 
 not seem to trouble them in the slightest degree, 
 
 290 
 
FIGHTING NATURE IN CANADA 
 
 but the thought that by carelessness they may 
 imperil others does seem to impress them, and for 
 the sake of others they will take pains which they 
 refuse to take in their own interest. 
 
 Another thing which these men will not do is to 
 take due care to avoid the flying fragments which 
 follow the explosion. Due arrangements are made 
 for safe refuges for the men, in which they can 
 shelter while the pieces of rock are flying about, but 
 the men frequently neglect to take advantage of 
 these. 
 
 Another thing which they will persist in doing is 
 to rush back and start work again before they are 
 sure that all the charges have exploded. Frequently 
 several charges are laid, and if all goes well these 
 should work simultaneously, or nearly so, but some- 
 times one will fail. Then it may lie dormant for a 
 time, to be awakened later by a chance stroke of a 
 pick or something of that sort and an explosion will 
 follow. 
 
 Owing to these risks this part of the work was the 
 most costly in human lives of any part of the under- 
 taking. 
 
 Let us now picture to ourselves the track for the 
 line duly prepared, that is to say, a roughly level 
 strip ready for the ballast, sleepers and rails. The 
 laying of the rails was done by a very remarkable 
 machine, known as a " track-layer." 
 
 This consists of a large, heavy truck, with a special 
 form of crane mounted upon it, which is pushed along 
 from behind by a locomotive. Immediately behind 
 the machine itself there follows a truck piled high 
 
 291 
 
FIGHTING NATURE IN CANADA 
 
 with rails, then the locomotive and finally trucks 
 with sleepers. 
 
 On one side of the track-layer is an iron trough 
 with a number of short rollers in it, the rollers being 
 driven round by a steam engine on the machine 
 itself. This trough extends backwards for a con- 
 siderable distance, as far, in fact, as the trucks of 
 sleepers. 
 
 When in action the whole train, as just described, 
 stands upon the rails just laid, the track-layer being 
 quite close to the end. Men in the trucks behind 
 throw sleepers on to the rollers in the trough, which, 
 since they are revolving, carry them forward and 
 shoot them down upon the ground just where they 
 are needed. Here a powerful gang of men receive 
 them and quickly haul them into place until enough 
 sleepers are down to support a fresh length of rail. 
 Then the crane-like structure passes along two rails 
 from the truck behind, and these are quickly joined 
 by fishplates to the ones last laid and spiked down 
 upon the sleepers. It should be explained here that 
 on this line chairs are not used as in the European 
 practice, but the rails have a flat flange on the 
 underside, so that they can stand directly upon the 
 sleepers with nothing more than a square plate of 
 iron between to distribute the weight upon the 
 wood, and the rails are fastened down by " dog 
 spikes," especially formed nails of huge dimensions, 
 the heads of which hook over the edges of the flange. 
 
 In this way the line is roughly laid, and the track- 
 layer with its attendant engine and trucks passes 
 on. The line is not, however, by any means finished, 
 
 292 
 
FIGHTING NATURE IN CANADA 
 
 for there is no ballast and it is not level. Therefore 
 the ballast train follows. This consists of trucks 
 with doors underneath, so that as the train slowly 
 proceeds the ballast can be let out, forming a ridge 
 between the rails. On the last car of the train is a 
 " distributer," a kind of plough which is drawn along 
 close to the rails, the " ploughshares " being so 
 shaped and so set that they level off the heap of 
 ballast between the rails and throw any surplus to 
 the sides. 
 
 That is about as far as mechanical aids can go. 
 The human mind is required for the last step, which 
 is to level and straighten out the line and pack the 
 ballast carefully, so that a strong, firm line may 
 exist capable of carrying heavy trains at a high speed. 
 
 So the gangs of platelayers come along to put in 
 the finishing touches. They raise those parts of the 
 rails which need it by means of jacks, straighten the 
 rails where necessary, and with their shovels and 
 beaters place the ballast beneath and around the 
 sleepers. When they have finished with the job 
 there is a railway, as we know the term, a carefully 
 adjusted and well-cared for track, along which the 
 trains can move. 
 
 This takes them a little time, particularly upon 
 embankments and other places where the ground 
 has been made up, because settlement is always apt 
 to occur at such places. They have to watch the line 
 very carefully, therefore, for a time, jacking up and 
 putting new ballast as may be necessary. It is not 
 long, however, before the line is ready for traffic. 
 
 Thus we see how man, with his persistency, his 
 
 293 
 
FIGHTING NATURE IN CANADA 
 
 ingenuity and his natural love for overcoming 
 obstacles, beats Nature in her wildest moods and 
 brings her to serve his own needs. 
 
 [The information contained in this chapter has been derived 
 from Mr. F. A. Talbot's, " The Making of a Great Canadian 
 Railway," by kind permission of the Author,] 
 
 294 
 
CHAPTER XXII 
 LONG ALPINE TUNNELS 
 
 THE Continent of Europe is cut up by the high 
 Alpine Range. Those of us who have had to 
 wrestle with the difficulties of translating the 
 writings of Caesar will remember that even in his 
 time the Alps were great obstacles to movement 
 from one part to another. With the larger popula- 
 tions of to-day and the greater need for inter- 
 communication between nations, these old obstacles, 
 while, of course, no worse actually than of old, 
 became more and more serious in the inconvenience 
 which they caused. 
 
 Mountains, naturally, are not the same height all 
 along the range. There are parts which are lower 
 than others, and these form the " passes " over the 
 range. A pass is, of course, merely a convenient 
 place for crossing the mountains, but the reason it is 
 convenient is because, generally speaking, it is lower 
 than elsewhere ; and secondly, the action of streams 
 and rivers have usually excavated a kind of transverse 
 valley leading up the pass. 
 
 Although a pass is a hollow, by comparison with 
 the surrounding heights, it has, nevertheless, a 
 summit or highest point, the roadway gradually 
 
 295 
 
LONG ALPINE TUNNELS 
 
 rising to it from one side and then falling away 
 again on the other side. 
 
 To illustrate this we may take the well-known 
 St. Gothard Pass in Switzerland. The road runs 
 for miles, gradually rising towards the pass itself, 
 following for the most part the valley which has 
 been cut by the River Reuss as it flows from the 
 high mountains down to the " Lake of the Four 
 Forest Cantons." After surmounting the pass the 
 road descends slowly on the other side to the plains 
 of Italy. 
 
 The railway, not unnaturally, follows very largely 
 the line of the old road along which Napoleon marched 
 his armies. It does so because just as the old road- 
 maker sought for the easiest gradients, so does the 
 railway-maker of to-day. 
 
 The railway engineer, however, is not satisfied 
 with the conditions which were deemed good enough 
 for road traffic. Consequently, when the railway has 
 ascended the fairly steep road to the foot of the pass 
 proper it boldly leaves it to the road to scale the 
 steepest part of the route, but itself dives into the 
 mountain-side and passes through a tunnel over 
 nine miles in length right through to the other side. 
 
 But even on the approach to the tunnel the railway 
 builder has resorted to devices whereby his line 
 shall be less steep than the roadway. A wonderful 
 example of this is seen on the St. Gothard line at the 
 little village of Wasen. The traveller, in passing 
 this beautiful spot, first catches a glimpse of the 
 village church high above him on the mountain 
 side, he being then at the bottom of the little valley. 
 
LONG ALPINE TUNNELS 
 
 A few minutes later he sees the church again, this 
 time, to his amazement, about on the same level as 
 himself, for now he, too, is on the hill-side. Again 
 he passes into a tunnel, on emerging from which the 
 village church is still visible and close at hand, but 
 far below, for he is now on the hill-side, even higher 
 up than the church. 
 
 The explanation of this is that tunnels have been 
 employed in order to lengthen out the track and so 
 make it less steep. 
 
 The line comes along at the lowest level, enters a 
 tunnel which forms a wide loop right inside the 
 mountain ; then, after a short interval in the open 
 air, it traverses a second loop-like tunnel, rising 
 steadily, of course, all the time. Both road and 
 railway, of necessity, rise the same number of feet, 
 but the increase in length due to the loop-shaped 
 tunnels enables the railway to rise more gradually. 
 It may be compared roughly to a spiral staircase cut 
 in the inside of the mountain. 
 
 On the Italian side of the pass a similar thing 
 occurs, but there the tunnels are, if anything, more 
 remarkable still, since they take the form of a spiral 
 or corkscrew, thus making a descent of many feet 
 right inside the mountain. There are other examples 
 of this kind of construction in other parts of the 
 world. 
 
 So much for the approaches to the long tunnels. 
 Let us now turn to the tunnels themselves. 
 
 The construction of these involves the overcoming 
 of difficulties not met with in shorter tunnels. For 
 one thing, they are very long ; for another, the land 
 
 297 
 
LONG ALPINE TUNNELS 
 
 above them is more or less inaccessible mountain, 
 where it is impossible to sink shafts. In ordinary 
 tunnels of any considerable length shafts are sunk 
 at one or more points along the line, and from the 
 bottom of the shafts boring is carried on in both 
 directions. This one shaft will roughly halve the 
 time necessary to construct a given tunnel, because 
 operations can be carried on from four points instead 
 of two. Two shafts will give six points instead of 
 two, so that two shafts will reduce the time by two- 
 thirds, and so on. Devices of this kind are impossible 
 with the Alpine tunnels, and so the work has to be 
 done from the two ends only. 
 
 Another great difficulty is the heat. As you bore 
 farther and farther into the earth the temperature 
 always increases. This is found in sinking wells, 
 where the rise is about one degree Fahrenheit for 
 every 60 ft. in depth, and the experience in these long 
 tunnels shows that this rise in temperature is largely 
 dependant upon the depth below the surface, for in 
 the Simplon Tunnel, which is about twelve miles 
 long, it was found that the temperature was about 
 one degree higher for every 67 ft. of depth below the 
 surface. Right at the centre of this tunnel, where 
 there was a great mass of mountain lying above, the 
 temperature of the rock was found to be 133 degrees. 
 
 This heat used to be attributed entirely to the 
 greater proximity to the centre of the earth, where, 
 no doubt, a much greater temperature exists than 
 upon the surface, since heat must have been escaping 
 freely from the surface for ages, whereas that in the 
 centre can only escape much more gradually. This, 
 
 298 
 
LONG ALPINE TUNNELS 
 
 however, did not seem to be quite sufficient to account 
 for the very rapid increase of temperature with 
 depth, and it is now believed to be due to a very 
 large extent to that newly discovered property of 
 certain matter called " radio-activity." 
 
 Everyone has heard of " radium," that strange 
 substance which is continually throwing off tiny 
 particles which under certain conditions can be 
 seen like microscopic fireworks. It is found, too, 
 that the immediate surroundings of a minute quantity 
 of radium are always slightly higher in temperature 
 than things less close. It is evident, therefore, that 
 radium also gives off heat, and apparently it is able 
 to keep on giving off heat for a very long time ; in 
 other words, the amount of heat stored up in radium 
 must be very great indeed. 
 
 This throwing off of heat and of small particles 
 is called " radio-activity," and is apparently due to 
 the breaking up of the atoms of which the stuff 
 consists. 
 
 Now radium is a very rare substance, but since it 
 is so very active a very small quantity of it dis- 
 tributed through the rocks which form the mountains 
 might easily cause this mysterious increase in tem- 
 perature. Moreover, although radium is the out- 
 standing example of radio-activity, there are other 
 substances which do the same thing, though to a less 
 marked degree, and it may be the presence of these 
 things in the rock which gives rise to the heat, even 
 though radium itself may be absent. 
 
 However that may be, this rise in temperature is 
 a very serious obstacle to the engineers who are 
 
 299 
 
LONG ALPINE TUNNELS 
 
 responsible for the boring of a long tunnel. The 
 measures taken to combat it are usually two ; first, 
 the supply of ample quantities of fresh air, which is 
 driven into the tunnel as it is made by huge fans, 
 frequently operated by the many streams of water 
 to be found in the vicinity of such work ; and second, 
 a supply of cold water conveyed through pipes and 
 sprayed about the workings, so as to cool both the 
 rock itself and the air. 
 
 When the tunnel is once through, that is to say 
 when the two borings have met in the interior of 
 the mountain, the trouble is to some extent solved 
 automatically, because the barometer is nearly always 
 higher on one side of the mountain than on the other* 
 with the result that there is induced a natural flow 
 of air through the tunnel. 
 
 In the case of the Simplon Tunnel, where, on 
 account of the enormous length, this difficulty was 
 more marked than in .any other case, special methods 
 were adopted which will be mentioned later. 
 
 The lengths of the chief Alpine tunnels are as 
 follows : Arlberg, 6J miles ; Mont Cenis, 8 miles ; 
 St. Gothard, 9| miles, and Simplon, 12 J miles. 
 
 The variations in length are largely due to the 
 varying heights at which the engineers decided to 
 abandon the open air and start boring into the 
 mountain. Obviously, it is cheapest to make as 
 much of the line as possible in the open air, and in 
 one case of an Alpine pass, the Brenner, they actually 
 succeeded in keeping to the open air all the way, 
 and carrying the rails right over the pass itself. 
 That is the only example of an Alpine pass, however, 
 
 300 
 
 
LONG ALPINE TUNNELS 
 
 which is traversed by rail otherwise than through a 
 tunnel, and in deciding where to commence boring 
 they are guided largely by three considerations. 
 
 First of all, the higher the mouth of the tunnel 
 the more likely is it to be blocked by the winter 
 snows ; on the other hand, the lower it is the longer 
 will the boring be and the greater will be the heat 
 encountered when doing it. Thirdly, there is the 
 question of gradient. As remarked earlier, the route 
 generally becomes more and more steep as the 
 summit of the pass is approached, and this fact, too, 
 has to be taken into consideration. 
 
 These long tunnels are usually perfectly straight. 
 This is to simplify the surveying operations by 
 which the tunnel, as it progresses, is steered, as it 
 were. 
 
 Just consider for a moment what this means. In 
 the case of the Simplon they started work at two 
 points over twelve miles apart, and from each of 
 these points a tunnel was driven in the direction of 
 the other, the idea being that they should join up 
 at a point inside the mountain. In due time (after 
 about seven years' work) they met, with this astound- 
 ing result : one tunnel was 8 ins. higher than the 
 other and 3| ins. to one side. The total length of 
 the tunnel when it was measured right through was 
 found to be within 31 ins. of the length which had 
 been calculated over the surface before the tunnel 
 was begun. 
 
 To put it another way, the task of the engineers 
 was to draw a straight line from one point six miles 
 long towards another point which they could not 
 
 301 
 
LONG ALPINE TUNNELS 
 
 see, and they were only 8 ins. wrong when they got 
 there. 
 
 In the face of an astonishing problem like this it 
 is not surprising that they make the tunnel straight, 
 as that simplifies the work very much indeed. As 
 explained elsewhere, the London tubes are steered 
 round various bends and corners, but the length 
 is so much shorter in those cases that the problem 
 is a much easier one. 
 
 The method employed is to survey the route first 
 of all upon the surface. A straight line, denoted by 
 suitable marks, is carried right across the mountain 
 from one starting point to the other. Then at each 
 end of this line there is set up an observatory, upon 
 which is mounted a powerful telescope, so placed 
 that it can first of all be directed at a distant point 
 upon the surface line and then right into the tunnel 
 itself. At intervals, as the work proceeds, an 
 illuminated mark is set up in the far end of the 
 tunnel and viewed through the telescope, and by 
 that a very slight deviation can be detected and set 
 right. 
 
 These long tunnels are usually on the whole level, 
 but sloping upwards from the ends towards the 
 middle simply in order that they may drain them- 
 selves naturally. In this respect the makers of a 
 mountain tunnel have a great advantage over the 
 builders of a subaqueous tunnel, for in the latter 
 case pumping has to be used upon a large scale and, 
 as in the well-known case of the Severn Tunnel, a 
 mishap may result in the whole workings being 
 drowned out for months. 
 
 302 
 
LONG ALPINE TUNNELS 
 
 An inrush of water is by no means unknown even 
 in tunnels high up in the mountains. In the Simplon, 
 for instance, a spring was struck, known as " The 
 Great Spring," which poured 10,500 gallons per 
 minute into the workings, and a hot spring which 
 poured in 3000 to 4000 gallons every minute at a tem- 
 perature of 114 degrees. It was not difficult to deal 
 with these, however, since the water ran out naturally. 
 
 The necessity of making the tunnels straight, 
 however, usually makes it impossible to have the 
 entrances at the most suitable points upon the 
 mountain -side for the trains to approach, and con- 
 sequently where the train enters is not generally the 
 true entrance to the tunnel* but merely the entrance 
 to a subsidiary tunnel which curves round and joins 
 the main, straight tunnel some distance inside the 
 mountain. 
 
 The actual work of boring is done by compressed 
 air. 
 
 There are two kinds of " rock-drill " used for the 
 purpose. These are machines which manipulate a 
 " tool " termed a drill, but which would frequently 
 be better described as a chisel. Some of these 
 machines turn the drill round and round, while 
 others employ a hammering action. In either case 
 the object is to bore a hole in the rock, at the bottom 
 of which can be placed a cartridge of explosive 
 material which, when fired, will break down the 
 rock. 
 
 Compressed air is not an economical means of 
 transmitting power, but it is very convenient for 
 work like this, and it has the additional advantage 
 
 303 
 
LONG ALPINE TUNNELS 
 
 in a hot tunnel that the air, as it escapes after having 
 done its work, helps to ventilate the workings. 
 
 In one case an ingenious arrangement was adopted 
 in which a jet of water under high pressure was 
 directed upon the rock about to be blown up, with 
 the result that the debris was at once carried right 
 away from the face and the men were able to resume 
 drilling operations immediately the explosion had 
 taken place, instead of having to wait for the broken 
 rock to be cleared away. Then the " spoil " is carried 
 away in small trucks, running on light rails laid for 
 the purpose. 
 
 It must not be thought, however, that the tunnel 
 is made full-size right away. A small tunnel, called 
 a heading, is first bored. This is only just large 
 enough for the workmen to stand up in, and wide 
 enough for the necessary two lines of rail for the 
 trucks. Sometimes the heading is at the top of what 
 will be the finished tunnel, but more frequently 
 it is at the bottom. Vertical shafts are then bored 
 upwards from the heading, and from these the rock is 
 attacked, so that as broken down it falls into the 
 heading, whence it is carried away. 
 
 The use of compressed-air machines for rock 
 drilling caused a great saving of time over the hand 
 drilling which used to be employed for such work, 
 but even with the best appliances a speed of five or 
 six yards per day on an average is very good progress 
 indeed. 
 
 Much depends upon the nature of the rock. If it 
 is soft it naturally comes away most quickly. Hard 
 rock takes more time to bore the holes and less of it 
 
 304 
 
 
 
LONG ALPINE TUNNELS 
 
 breaks away with each explosion. The worst rock 
 of all to deal with, however, is that where parts are 
 hard and parts soft. The drill then probably strikes 
 a spot where it penetrates both sorts at once, with 
 the result that the hard part deflects it into the soft 
 part and probably either causes it to jam tightly or 
 else to break. 
 
 The Simplon Tunnel was made for a single line 
 only, the intention being to make a separate tunnel 
 for a second line as soon as the traffic should justify 
 it. The two headings were made, however, although 
 only one was enlarged into a finished tunnel. At 
 frequent intervals a short cross-heading connected 
 the other two, and this was found very useful for 
 ventilation purposes, for air could be driven along 
 one to find its way through the cross-headings and 
 back through the other, thus keeping up a constant 
 circulation. 
 
 The rocks encountered in these mountains are of a 
 very varied character, but in most cases they are 
 firm enough to need no support other than their own 
 strength. Where, however, they are so soft that they 
 tend to move under the weight of the mass of matter 
 lying above them they need to be strengthened 
 temporarily with timber, which is ultimately taken 
 out gradually and replaced by masonry. 
 
 Thus some tunnels are in part lined with masonry 
 and in part left just as they were first hewn out of 
 the solid rock. It all depends upon the nature of 
 the rock, and every inch, almost, has to be judged 
 upon its own merits. 
 
 The Simplon Tunnel is lined throughout, but there, 
 u 305 
 
LONG ALPINE TUNNELS 
 
 again, the thickness of the lining is varied according 
 to the nature of the rock. In some parts it consists 
 of granite masonry 5 ft. thick. 
 
 During the construction of the St. Got hard Tunnel, 
 in order not to make the atmosphere more oppressive 
 than could be helped, compressed-air locomotives 
 were used to haul the trucks of broken rock out from 
 the workings, but, of course, whether for construction 
 purposes or for actual working, electricity is pre- 
 eminently the best form of traction for tunnels like 
 these. 
 
 The Simplon Tunnel is worked by electric loco- 
 motives which pick up their energy from overhead 
 wires. The system employed is what is known as 
 the " three-phase " system, in which three separate 
 alternating currents act together. It requires three 
 separate conductor wires, but these can easily be 
 arranged for where there is a solid masonry roof 
 from which they can be suspended. 
 
 One other feature of the Simplon Tunnel should be 
 mentioned. There is an enlarged portion in the heart 
 of the mountain, to accommodate a short piece of 
 double line, where two trains can pass each other. 
 But for this it would have to be worked as a single 
 line section twelve miles long, but by this means it 
 is divided into two six-mile sections. 
 
 306 
 
INDEX 
 
 Accelerator valve, 99 
 " Acid " and " Basic " pro- 
 cesses, 132 
 Air-locks, 232 
 Air pressure in the " tubes," 
 
 238 
 
 Alport, Sir J., 18 
 Alternating current, 182 
 " Atomizing " oil, 90 
 Automatic stop, The, 184 
 " Automatics," 40 
 
 Ballast, 117 
 Ballast, Laying, 293 
 Basic slag, 133 
 Bessemer process, The, 129 
 Blast furnaces, 124 
 Blast-pipe, The, 65 
 Block system, The, 159 
 Block telegraph, 171 
 " Blower," The, 66 
 Boiler, The, 60 
 Boiler shop, The, 52 
 Booking office, The, 20 
 Bowstring girders, 149 
 Brake, Types of, 75 
 Brass foundry, The, 56 
 Bridge-yards, 141 
 Bridges, 137 
 Brunei, 24, 231 
 Bus bars, 261 
 Bush fires, 36 
 
 Cabins, Signal, 163 
 Canada, 29 
 
 Canadian Pacific Ry., Mak- 
 ing the, 34 
 Catch points, 95 
 Central London Ry., 175 
 Chairs for rails, 118 
 Charging machine, 134 
 City and S. London Ry., 175 
 " Clay belt," The, 36 
 Clayton's fogging machine, 
 
 204 
 
 Combinator, The, 249 
 Compound engines, 73 
 Compound locomotives, 77 
 Commutator, The, 262 
 Compound v. Simple, 85 
 Compressed air machines, 
 
 304 
 
 Collectors, 268 
 Condensation, 81 
 Conductors, 266 
 Connecting-rod, The, 69 
 Continuous brake, The, 94 
 Contractors, 114 
 Controller, The, 218, 264 
 Converter, The, 129 
 Cranes, Electric, 49 
 Crank, The, 69 
 " Cropper," The, 142 
 Cross-head, The, 69 
 44 Cupola," The, 56 
 
 30? 
 
INDEX 
 
 Currents, Alternating and 
 
 direct, 182 
 Cylinders, The, 72 
 Cylinders, High-pressure, 83 
 
 " Dead man's handle," The, 
 
 265 
 
 Detectors, 170 
 Diagrams, 220 
 Dome, The, 62 
 Dorada Ropeway, The, 274 
 Drain-cock, The, 82 
 Drilling machines, 47 
 Driving wheels, 75 
 Drop-forgings, 52 
 
 Eccentric, The, 70 
 Ejector, The, 100 
 Electric currents, 256 
 Embankments, 110 
 Engineer's office, The, 113 
 Erecting shop, The, 58 
 Escalators or moving stairs, 
 
 250 
 
 Excavating shield, The, 238 
 Exhauster, The : 101 
 Explosives, Handling, 290 
 
 " Fettling," 57 
 
 Fire-box, The, 62 
 
 Flanging presses, 52 
 
 " Fly-over," The, 120 
 
 Fog, 201 
 
 Fog signals, 201 
 
 " Formation level," 117 
 
 Furnaces, Feeding the, 134 
 
 Ganger, The, 120 
 
 Gauge, Curious dimension 
 
 of the, 24 
 Goods traffic, 217 
 
 Goods, Transport of, 19 
 Gradients, 37 
 
 Grading machine, The, 286 
 Grand Trunk Pacific Ry., 
 
 284 
 
 Grand Trunk Pacific,The,28 
 G.N.R. control room, The, 
 
 219 
 
 Great Western Ry., The, 24 
 " Grout," 239 
 Guard rails, 119 
 
 Hayes, C. M., 29 
 Hematite, 132 
 
 Illuminated diagrams, 198 
 Impedance, 182 
 Impurities in iron ore, 127 
 Indicators, 173, 244 
 Ingot moulds, 133 
 Injector, The, 74 
 Inns, 20 
 "Instrument shelf," The, 
 
 164 
 
 Interlocking, 161 
 Interlocking apparatus, 
 
 The, 165 
 
 Iron foundry, The, 53 
 " Iron man," The, 144 
 Iron ore, 124 
 
 Ladle for molten metal, 55 
 Lathes, their fittings and 
 
 attachments, 40 
 Lattice girder, The, 147 
 " Length " of line, 120 
 Light railways, 25 
 Link, The, 71 
 Locking trough, The, 166 
 Lock and block, 179 
 Locomotive works, 39 
 
 308 
 
INDEX 
 
 Macdonald, Col. F. R., 90 
 " Machine shop," The, 39 
 Magazine train describer, 
 
 247 
 
 Manizales, 271 
 Mariquita, 271 
 Mild steel, 123 
 Motor traffic, 22, 25 
 Moulds and patterns, 54 
 
 Navvy, The, 115 
 Non-return valve, 98 
 
 Oil as fuel, 88 
 
 Oil engines, 86 
 
 Oil v. steam, 86 
 
 Open hearth process, The, 
 
 130 
 Opposition, The mistake of, 
 
 21 
 
 Overlap, The, 184 
 Ozone in the " tubes," 240, 
 
 253 
 
 Parcel traffic, 20 
 Parliamentary powers, 111 
 " Patterns," 54 
 Permanent way, The, 120 
 Permissive tablet system, 
 
 156 
 
 Pig iron, 123, 127 
 Pilot-man, The, 151 
 Pistol hammer, The, 53 
 Piston, The, 66 
 Planing machines, 45 
 Plate-girder bridges, 138 
 Platelayers, 122 
 Points and crossings, 119 
 Points, facing and trailing, 
 
 168 
 
 Points, locking and un- 
 locking, 155 
 
 Poles of a magnet, The, 225 
 Portage, 35 
 Ports, The, 67 
 Power signalling, 192 
 Power-stations, 259 
 Pressure gauge, The, 68 
 Promoters and Directors, 
 
 113 
 Puddling furnace. 
 
 Radio-activity, 299 
 Rail with rack, 23 
 Rail v. Road, 26 
 Railway, Scheming a, 110 
 Rails, 122 
 Ramp, The, 207 
 Raven system, The, 212 
 Regenerative furnaces, 181 
 Regulator, The, 63 
 Relay, The, 179 
 Release valve, 102 
 Releasing reservoirs, 102 
 Reversing the engine, 69 
 Rivets, 144 
 Robinson, Wm., 176 
 Rocky Mountains, 37 
 Roe, J. P., 275 
 Rolling mills, 135 
 Ropeways, 273 
 
 Safeguards, 27 
 Sand blast chamber, The, 57 
 Saws for cutting metal, 142 
 " Scarab," The, 93 
 Schedules of quantities, 113 
 Selective instruments, 222 
 Semi-automatic signalling, 
 
 189 
 Shearing machine, The, 58, 
 
 142 
 Shield, The, 231 
 
 39 
 
INDEX 
 
 Shunting, 197 
 
 Signalling, Early, 160 
 
 Simplon tunnel, The, 300 
 
 Single lines, 150 
 
 Slag, 126 
 
 Slide-valve, The, 66 
 
 Slotting machine, 50 
 
 Slough, Accident at, 212 
 
 Smoke-box, The, 65 
 
 Soaking pit, 135 
 
 South-Western Ry., The, 21 
 
 Staff system, The, 151 
 
 Stationmaster, The, 216 
 
 Steam-chest, The, 67 
 
 Steam expansion, 80 
 
 Steam hammers, 50 
 
 Steam navvies and mechan- 
 ical shovels, 115 
 
 Steam pressure, 78 
 
 Steam-tightness, 68 
 
 " Stiffeners," 140 
 
 Stock rail, The, 119 
 
 Stripper, The, 133 
 
 Super-heating steam, 80 
 
 Surveying, 30 
 
 Surveying parties, hard- 
 ships of, 35 
 
 Surveying the route of a 
 tunnel, 302 
 
 Sykes' audible cab signal, 
 207 
 
 Sykes, W. R., 176 
 
 Tablet system, 153 
 Tank, The, 75 
 Temperature in tunnels, 
 
 298 
 
 Templates, 141 
 Tenders and Tenderers, 113 
 Tension or pressure, 262 
 
 Testing bridges, 149 
 Theodolite, The, 235 
 Third class carriages, 18 
 Three position upper quad- 
 rant signal, 188 
 Track circuit, The, 175 
 Track-layer, The, 291 
 Tracks, Temporary and per- 
 manent 117 
 
 Train pipe, The, 96, 100 
 Transformers, 263 
 Trappers and Indians, 334 
 Travelling in old times, 17 
 Trestles for ropeways, 281 
 Trevithick, R., 22 
 Triple valve, The, 106 
 " Trough-flooring," 145 
 " Tubes," The, 241 
 Tunnels, 230, 295 
 
 " Underground," The, 241 
 
 Vacuum and Compressed 
 
 air, 96 
 Ventilation of the " tubes," 
 
 239 
 Vertical boring mill, 50 
 
 " Walking " a derrick, 148 
 Water in tunnels, 303 
 Western Electric Co., 219 
 Westinghouse brake, 103, 
 
 193 
 
 " Wet " steam, 62 
 Wheels, Types of, 73 
 Wrought iron, 127 
 
 Yellowhead Pass, The, 38 
 Yerkes, C. J., 242 
 
 Mayflower Press, Plymouth, England. William Brendon & Son, Ltd. 
 1921 
 
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