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A - PRACTICAL INQUIRY LAWS OF EXCAVATION AND EMBANKMENT UPON RAILWAYS; BEING AN ATTEMPT TO DEVELOPE THE NATURAL CAUSES WHICH AFFECT THE PROGRESS OF SUCH WORKS, AND TO POINT OUT THE MEANS BY WHICH THE GREATEST EXPEDITION AND ECONOMY IN EXECUTION MAY BE OBTAINED. - WITH AN APPENDIX AND PLATES, ILLUSTRATIVE of THEIR APPLICATION IN PRACTICE. ****-*. . ’’ wº. . BY A RESIDENT AssistANT ENGINEER, - * | * * * e º . \ , ; Ut varias usus meditando extunderèt artes ; : Paulatim. - VIRGIL. - - LONDON : SAUNDERS AND OTLEY, CONDUIT STREET. 1840. LONDON : BLATCH AND LAMPERT, PRINTERs, GROVE PLACE, BROMPTON. s TO CAPTAIN W. S. MOORSOM ENGINEER IN CHIEF TO THE BIRMINGHAM AND GLOUCESTER RAILWAY, &c. &c. THE FOLLOWING I N Q U I R Y IS DEDICATED, C O N T E N T S. PART I. SECTION 1-Preliminary Remarks SECT. SECT. SECT. SECT. SECT. 2.—Statement of the principal experiments, made with reference to the removal of earth, with com- mon railway wagons; accompanied by explanatory observations tº g & * 3.—Analysis of the experiments given in the pre- vious section e º sº e 4.—Investigation of the fundamental formulae, with a few practical applications of them . 5.—Investigation of the formulae of limitation, and development of the causes which particularly affect the progress of embankments upon rail- ways PART II. 6.—An inquiry into the effects of the lead, show- ing the alterations necessary in the general ar- rangements of excavations and embankments 7.—Determination of the amount of friction inci- dent upon contractor's rails PAGlº, 1() 20 30 41 56 75 viii CONTENTS. SECT. 8.—Summary of the principal formulae and facts PAGE . connected with the removal of materials by means of wagons and horse power . tº . 103 SECT. 9.-Investigation of the system of removing soil by means of barrows and human labour . 130 APPENDIX. Notes, and explanation of technical terms . • . 155 Description of Plates tº g ſº g & . 163 P. R. E. F. A. C. E. THE inquiry pursued in the following Treatise, into the laws which govern the process of exca- Vation and embankment upon railways, was not originally undertaken by the Author for the pur- pose of publication; his object, upon commencing it, being to mature his private judgment in the estimation of such undertakings generally. Nor was it for some years after the first investigations were made for this purpose, that the real impor- tance of the subject to the engineer—the small amount of practical knowledge upon it extant, and the unaccountable mystification or oversight of it by scientific men, combined with the re- markable facility and accuracy of the formulae to be derived from it—suggested to the Author, the propriety of arranging and selecting, from amongst B X PREFACE. the various desultory papers which he had written, from time to time, those which seemed more imme- diately to bear upon the practical results. All members of the engineering profession must have been already convinced of the utility to be derived from an inquiry like the present, when it can be made practically available; es- pecially if they have ever been engaged in the execution of large cuttings and embankments; or observed the remarkable discrepancies which exist between the recorded opinions of celebrated engineers, given before Committees of the House of Commons, and elsewhere; not only as to the cost, but as to the mode best adapted, and the time required for the completion of such works. But more so, if they have observed, that up to the present moment, few men, not even con- tractors, make out their estimates of expenditure and time upon any fixed principles—the accu- racy of their estimates, in all cases, being de- pendent upon the conjectural instinct of the per- sons who may make them—and that hence, doubt- less, arose the late disastrous effects upon the railway system—public confidence being unavoid- ably forfeited, in consequence of the glaring discrepancies between the supposed and actual outlay required for their completion. These discrepancies have been so various and frequent, that it would be at present unnecessary, PREFA CE, xi and perhaps invidious, to make any allusion to them; further than what is merely necessary to point out the advantage that may be derived, from an experimental inquiry into the causes upon which they depend; and a clear statement or analysis, of the means by which they may be in future obviated, as afforded by the results of such an inquiry. That the above object has been wholly at- tained in the present work, the author will not take upon himself to determine; but he is led anxiously to expect, that it presents such a theo- retical and practical insight into the principles of railway cuttings and embankments, as will enable any person, moderately acquainted with the sub- ject, to avoid making any serious difference be- tween the estimated and actual cost. There is no department in the varied range of engineering practice, which has been so lamentably neglected as that which is comprised in the pre- sent treatise; and as no previous author has in- vestigated it, a more than usual share of indul- gence is claimed from the reader. A few theo- retical men have undoubtedly alluded to the subject; of whom Mahan, an American writer, in the appendix to his Elementary Treatise upon Civil Engineering, has given the most comprehen- sive elucidation that has been hitherto attempted ; but so practically erroneous and speculative, are B 2 xii PREFACE, the mode of investigation adhered to, and the results arrived at, that it may be considered worse than nugatory; because all such methods of treating natural subjects, have a tendency to pervert the mind of the student from the train of thought indigenous to them, and the absolute importance of a personal knowledge of facts, into an abstract and conventional habit of viewing all phenomena purely practical—making the pheno- mena coincide with preconceived theoretical notions, instead of correcting theory by the phe- nomena.” Indeed, few writers who have applied themselves to engineering subjects are free from this tendency—the Compte de Pambour, perhaps, alone excepted, whose work upon the Locomotive Engine is a perfect model of that simplicity and sound judgment, so desirable in the treatment of every subject connected with natural philosophy. If the present inquiry is not altogether as free from the above-mentioned stricture, as the Author would wish it to be, he nevertheless entertains a hope, that merely on that account it will not be exempt from the approbation of the engineering profession ; for he is strongly impressed with an idea, that its appearance was not altogether un- * It may be as well to state, that these remarks are not intended to apply, to any other portion of Professor Mahan’s valuable treatise, than that which treats of earthwork. In other respects, as an elementary work, it ought to be perused by every professioual student, PREFA CE. xiii called for, if only for the purpose of attracting more general attention to that department in en- gineering of which it treats. However, should it have the eventual effect, of drawing the attention and talent of men who have more leisure, and are conversant with the treatment of similar in- vestigations, one advance, at least, will be made towards the object which induced the publication, in the following pages, of the results derived from a few years of personal experience and close attention to the subject. The theory and mode of induction adopted, will be found as simple, and at the same time as comprehensive, as the nature of the subject would admit of ; every endeavour having been made to exclude what was foreign or only collateral to the main features of the inquiry, and render the whole as easy as possible; consistent with a thorough comprehension of each department, and that mo- derate acquaintance with the elementary prin- ciples of science, which almost every individual interested upon such points has acquired. With respect to the data upon which the theory is founded, it may be observed, that they are common to the observation of every person, who wishes to give his attention to the several arrangements connected with the execution of cuttings and embankments, when worked with a proper force, and under good management; and, xiv. PREFACE. that in such cases, although a slight variation, in favour of larger results, may occur under particu- lar circumstances, yet, that the average of the work done in a given time—a year for instance— will in no case exceed the results given by the formulae deduced from this inquiry. In conclusion, it may be proper to remark, that the emoluments of the Earthwork Contractor have not been interfered with in any way; but, on the contrary, that he is likely to obtain much profit- able information, by being enabled to render himself thoroughly conversant in the most im- portant points connected with his particular calling, and to manage his works upon fixed principles, and consequently more economically. Bredom's Norton, March 4th, 1840. A PRACTICAL INQUIRY, &c. PART I. SECTION I.-Preliminary Remarks. BEING perfectly sensible of the great circum- spection and clearness, with which all opinions and theories upon practical subjects ought to be advanced, especially, when they are for the most part at variance with preconceived notions upon them ; we have been induced to commence in limine, and relate in detail the several circum- stances by which the following inquiry has been influenced. We are moreover convinced that, in doing so, we are doing no more than our duty towards the reader, when it is considered that the subject is entirely new ; for there is nothing more useful, when such is the case, than explaining, as elaborately as possible, the gradations by which 16 PR'ELIMINARY REMARKS, conclusions are arrived at, link by link; as it affords others the opportunity of pursuing similar investigations with greater facility, by means of the observations they are enabled to make upon the points on which the author has, or has not, been successful in giving a satisfactory elucidation. With these views, we offer the following pre- liminary remarks. The original motive which induced us to under- take the following investigation, was—as we have mentioned in the preface—simply, to mature the judgment in the estimation of cuttings and em- bankments generally; nor had we, at the time, the slightest anticipation that the causes of an effect, comprehending so many various details, and seemingly so anomalous, could be grasped and confined within certain rules and modes of action, either in detail or in the aggregate, as be- came subsequently evident. The first and principal department connected with the execution of earthwork, to which we directed our attention, was that which comprises the removal of earth, by means of wagons * drawn by horses over the common temporary roads used by contractors; and the second, that which may be denominated the barrowing system, or the removal of soil with the common wheel- barrow. * Wide Appendix, Note 1. PRELIMINARY REMARKS. H7 After making several observations in the first department—for the purpose of obtaining an average estimate of the quantity of work which a given force could perform, in a given time, when applied in the usual manner—and upon comparing them, it became so evident that the estimates derived from each set of experiments, varied ac- cording to the arrangements adopted upon the particular work to which it referred; that we found it useless to attempt arriving at any satisfactory conclusions, without entering into a thorough in- vestigation of the general principles developed in the system. For this end, we found it necessary to undertake a series of observations and experi- ments upon a much more extended scale than was originally attempted. In contemplating the results of these observa- tions, and endeavouring to arrange them methodi- cally, much difficulty was experienced, and dissatisfactory conclusions sometimes arose out of the same experiments; this led us to suspect that there was some mode of calculation peculiar to them, or that some cause, of which we remained ignorant, affected them; accordingly several addi- tional sets of experiments were undertaken at different times, and under various circumstances, upon the same works, and a closer attention given to the details; until we found that the main points 18 PRELIMINARY REMARKS. to be taken into consideration, in order to render them fit for the application of any mode of cal- culation, were—the time spent in filling the wagons, —the rate of speed at which they could be drawn by the horses, and the time spent in tipping them— each separately. The results of the experiments made upon these points, produced the following conclusions; viz:—that the quantity of work done in any instance, varied with the rate of speed at which the wagons were removed from cutting to embankment, and the number of wagons which could be tipped or emptied over the head of the embankment in a given time—the latter bear- ing a direct proportion to the height and rate of slope to which the sides of the embankment were to be finally dressed off; but that the number of getters and fillerst produced no sensible effect upon the progress of the work; being limited by the number of wagons in each set, and these again by the breadth of the tip or battery-head. We also perceived that the first of these, or the time spent while each set of wagons was being removed from cutting to embankment, could be calculated for any increase or decrease of lead, by applying the laws of the arithmetic series, when once the rate per mile per hour at which the horses travelled was determined ; and that the latter, or the number of wagons that could be tipped in a * Wide Appendix, Note 2. f Wide Appendix, Note 3. f Wide Appendix, Note 9. PRELIMINARY REMARKS. 19 given time, was of course variable, inasmuch as the height and rate of slope, to which the sides of each embankment were to be finally dressed off, were variable. When these conclusions were confirmed by repeated observations, the experiments hereafter detailed, and several others, were submitted to a method of calculation founded upon the principles of the common arithmetic series; and the results were found to agree exactly with practice. By using this method of calculating, it also became evident, that the quantity of work done, could in any case be obtained, by merely knowing the number of wagons used, and the breadth of the tip ; * provided the wagons were worked with their proper compliment of men and horses. The adoption of the arithmetic series—as the basis of the calculations for finding the number of wagons that could be removed, from cutting to the head of an embankment, in a given time— when the length of the leadt was also given—by a slight modification, enabled us, subsequently, to arrive at the formulae for variable leads; which will be found of great use, in those cases where the head of an embankment progresses rapidly; but more particularly, where side-tippingi is re- sorted to in dressing off slopes, &c.S As the formulae for calculating the number of * Wide Appendix, Note 4. + Wide Appendix, Note 5. t Wide Appendix, Note 6. § Wide Appendix, Note 7. 20 PRELIMINARY REMARKS. wagons that can be tipped under both these cir- cumstances, (according with the usual arrange- ments) have been rendered generally applicable, the cost per wagon, incident upon any length of lead—variable or constant—may be easily obtain- ed; as for this purpose, it is only requisite to know the rate of wages for a day labourer, and the cost of maintaining a horse per diem, in the neighbour- hood of the works;–due allowance being made for superintendance, and per-centage upon the capi- tal sunk, in procuring the proper materials for their execution. It was intended to give detailed estimates under these heads; but the prices of labour are so variable in different places, that a separate estimate would be required for each, in order to render them useful. This intention was therefore abandoned; and it is believed, without affecting the utility of an inquiry relating to the development of general principles. The process of induction by which the formulae above referred to were arrived at, laid open a much larger field for inquiry than we were ori- ginally prepared to expect; and indicated that the system of arrangement hitherto adopted, in the conveyance department especially, was far from being perfect. With the prospect of finding out where the imperfection lay, and the princi- ples by which it might be corrected, the subse- quent part of the inquiry was entered upon.— PRELIMINARY REMARKS. 21 After some consideration, it became obvious that to effect this purpose, the first point to be deter- mined, was the number of wagons required for producing the most effective result upon a given length of lead: in determining this, little difficulty was experienced; as it was not found necessary to enter upon principles of calculation different from those which were adopted in the first in- stance; and was so far satisfactory, inasmuch as it rendered the details of the subject unique in prin- ciple. From the process of induction by which this point was established, we came to a knowledge of the peculiar fact, that at certain exact periods in the progress of the works, an increase in the num- ber of sets of wagons” becomes necessary—the law of increase also agreeing with that of an arithmetic series; but leaving a greater common difference than the former. The periods at which this increase in the number of sets of wagons be- comes necessary, will be found to correspond with every twenty-five chains of increase in the length of the lead, or distance between the face of the cutting and the head of the embankment. This curious fact could never be obtained with sufficient accu- racy by actual observation; for it branches, as it were, adventitiously, out of the previous calcula- tions: a deficiency in the quantity of work done, * Wide Appendix, Note 8. 22 PRELIMINARY REMARKS. would certainly be experienced as the lead became longer; but it is difficult to suppose, that the cause of such deficiency, or the particular mode in which it might be remedied, could be discovered by mere observation, in a case where there are no palpable appearances to argue from. Having ascertained the number of sets of wagons requisite for working any length of lead, we were led to find the number in each set, that would ensure the greatest expedition in tipping, according with the dimensions of the battery head; and this, it will be seen, depends upon the time which a single wagon will take, in being drawn from the siding next the head of the embankment, backwards and forwards, including the tipping; and the number of sperms, or shunt roads, that can be laid abreast of the embankment. The results of the formulae we have given, for determining the two latter quantities—viz. the number of sets of wagons, and the number of wagons in each set—show clearly, that the present system of excavating cuttings and forming embankments is imperfect, as regards the ar- rangement of the sets of wagons, and the number placed in each set; because they prove, that both vary with the increase or decrease in the length of the lead, and the breadth of the tip ; whereas in all works of this description which we have PRELIMINARY REMARKS, 23 had an opportunity of examining, the number of sets of wagons were invariably three; and the number of wagons in each set bore a direct pro- portion to the area of the face of the cutting; or in other words, consisted of the greatest number of wagons that could be filled simultaneously; and this arrangement has been hitherto sanctioned by the universal dogma, that “upon the area of the face of a cutting, or the number of wagons which can be filled in it together, depends the facility of working it.” As subordinate to the foregoing points, we have given the load proper for an ordinary horse, expressed in wagons; and in order to establish this, several experiments were undertaken, to determine the amount of friction due to the ordi- nary roads and wagons, made use of by earthwork contractors. The results of these experiments have been calculated in the ordinary way, from the angle of friction. In conclusion, we have to add, that experi- ments and formulae have been also given for bar- row work; but as there is not any material difference in the nature of the observations, or the principles upon which they have been treated, any particular remarks here, upon that portion of the inquiry, would be superfluous. Having thus far detailed the principal facts connected with the inquiry, it remains for us to 24 PRE LIMINARY RE MARKS, remark, that the reader will find the general theory to hold good, whether the data, upon which each formula is founded, exactly coincide with his own observations or not, with reference to any par- ticular system of earthwork which he may examine ; or, in other words, that the formulae point out the method of arrangement for all observations of a similar nature, and are univer- Sally applicable; as, for instance, to experiments upon carting, or the excavation and conveyance of earth, for the formation of turnpike roads; in which cases, although the quantities representing each factor in the general formula, would con- siderably differ; yet the laws which they will be found to obey, are identically the same, and sub- ject to the same method of calculation—the difference altogether depending upon the differ- ence in the amount of friction which exists between the two modes of transit made use of. SECTION II. Statement of the principal earperiments made nith reference to the removal of earth nith common railway nagons, accompanied by earplanatory observations. Of the several experiments which were made from time to time, in order to ascertain the effect EXPERIMENTs, ETC. 25 produced by the common system of arrangement. upon different works, we have selected those given in the present section as being the most correct; having been found to agree best with the average of the greatest number of experiments that were undertaken. Indeed the difference be- tween any two was so trifling, that it would be prolix, if not useless, to insert them all; be- sides, the nature and compass of the present trea- tise did not admit of its being done; and we were of opinion, that it was requisite to state only so many of the experiments, as would afford suffi- cient data to show the accuracy and eatent of the investigations. However, should any reader not deem them sufficiently extensive for this purpose, he cannot ſail in having frequent opportunities, for procuring similar observations, “ad libitum,” in his daily practice, or by application to the foremen of the works he is engaged on. TABLE 1. Showing the results of four experiments made upon the number of wagons tipped, in a given time, for the repair of the permanent way of the Great Western Railway, in August, 1838:— C EXPERIMIENT'S WITH EXPERIMENTS UPON THE GREAT WESTERN RAILWAY. No. of | No. of No. of | No. of | No. of º Nos. wagons IOCIn horses wagons. hours lead in REMARKs. working. working-working, tipped. |worked. | Chain. I 16 48 4 109 8 60 The average time which elapsed, from when each set of 2 | 16 || 48 || 4 || 112 || 8 || 60 ºl..." - til it returned emp- ty, was 50.50 mi- 3 16 4 8 4 | 1 l 8 6 0 nutes. In these experiments the horses worked with apparent ease, when the wagons were once in motion; nevertheless, it was evident that a greater load would have distressed them. The material which was removed was gravel for ballasting the road; and each wagon, when filled level, contained fifty-six cubic feet of gravel; and when heaped, eighty-one cubic feet. In the above experiments all the wagons were heaped. From this table we find, that the average work done by twelve men, and one horse, with four wa- gons, working for eight hours, was the excavation, filling, removal, and tipping, or emptying, of 27.66 wagon-loads of gravel, each wagon-load containing eighty-one cubic feet; besides the drawing back the empty wagons, after being tip- ped, to the spot where they had been first filled; CONTRACTORS’ WAGONS. 27 when the length of the lead, or distance, between the points where the gravel was excavated and deposited, was sixty chains, or three-quarters of a mile. This being the average amount of work done by forty-eight wagons, twelve horses, and a hundred and forty-four men, working for eight hours, as will be seen by an inspection of the table. TABLE 2. Showing the results of four experiments, upon the number of wagon-loads removed to embank- ment from side cutting, in a given time, upon the Birmingham and Gloucester Railway, at Eckington, during the month of November, 1838. EXPERIMENTS UPON THE BIRMINGHAM AND GLOUCESTER, RAILWAY, ON THE ECKINGTON EXTENSION CONTRACT. i... No. of No. of No. of No. of lºſſ. gons of the Nos. working_* horses wagons | hours lead in REMARKs. - in a se. working-working. tipped. |worked. chains. l 4 12 2 35 8 40 The average #. 2 || 8 || 24 || 4 || 69 || 8 || 40 |V}...”.”; - ..., : the tting ed, un- 3 || 4 || 12 || 2 || 34 || 8 || 40 |jº. ty, was 36 minutes. 4 4 12 2 36 8 40 C 2 28 EXPERIMENTS WITH These experiments were made during the exca- vation of the side-cutting, * near the village of Eckington, on the Birmingham and Gloucester Railway; contracted for by Mr. Henry Milne of Worcester, and known as the “First extension of Eckington contract.” The horses were in high condition, but could not draw more than two wagons each ; although, in general, they performed their work with ease. The road over which the wagons worked, consisted of the temporary rails generally used by contractors, laid upon cross sleepers; and was also level, and in good order. Each wagon contained 49.28 cubic feet, when filled level, and when heaped, 65.72 cubic feet. The material excavated was the blue lias clay, laminated, and very hard ; and in all the experi- ments the wagons were heaped. From this table we find, that upon an average, two horses, twelve men, and four wagons, exca- wated, filled, removed to embankment, and tipped 34.80 wagon-loads, besides drawing back the empty wagons, when the number of hours, actually worked, consisted of eight, and when the length of the lead was forty chains, or half a mile; for this is the average of the quantity of work done—as shown by examination of the table—in eight hours, by sixty men and ten horses, with twenty Wagons. * Wide Appendix, Note 13. wº contRACTORs' wagoNs. 29 . TABLE 3. Showing the most correct of a series of expe- riments, made upon the number of wagon-loads removed from cutting to embankment, in a given time, on the Birmingham and Gloucester Rail- way, at Bredon's Norton; between November 1838, and April 1839. -- EXPERIMENTS UPON THE BIRMINGHAM AND GLOUCESTER, RAILWAY, CONTRACT 4. G., AT BREDON'S NORTON. No. of No. of | No. of | No. of | No. of Length wagons of the Nos. workin men horses wagons | hours lead; REMARKs. § * g - ead in in . . working.working. tipped. |worked. chains. I 12 36 6 131 10 40 2 8 24 4 88 10 40 The average time which elapsed, from 3 || 8 || 24 || 4 || 86 || 10 | 40 ||...”. . º UIIl- 4 || 6 || 12 || 3 | 66 | 10 | 40 ||. 5 6 12 3 65 10 40 These experiments were made upon a large work, near the village of Bredon, on the Birming- ham and Gloucester Railway; called the “Bre- don's Norton Portion;” in which, upwards of 240,000 cubic yards of excavation, through the 30 EXPERIMENTS WITH blue lias clay, was led from cutting to embank- ment. The contract was taken by Mr. George Williams, of Birmingham, who had recourse to all the usual expedients for speedily completing the work. The horses were in very good condition, con- sidering the harassing nature of the work which they had to perform: in one or two instances, which came under our observation, when acci- dents happened to some of the horses, three wa- gons were attached to a single horse; but so evi- dent was the distress the animals laboured under in such cases, that it seemed impossible, if tried, that they could continue drawing so heavy a load for more than an hour; and to give motion to the wagons at starting, it was always found ne- cessary to apply a lever to the spokes of the wheels. But when the number of horses bore the same proportion to the number of wagons, as that shown by the table, they endured the work without any visible detriment. The road, over which the wagons were drawn, was level, and consisted of the ordinary rails used by contractors, laid upon cross sleepers;* the wagons contained the same quantity of materials; and the lias excavated exhibited the same fea- tures, as stated under the head of the previous * Wide Appendix, Note 10. CONTRACTORs' wa GONs. 3 i table. The wagons were all heaped in these ex- periments also. From this table we perceive that 43.60 wagon- loads were excavated, filled, removed from cutting to embankment, and tipped, by two horses, four wagons, and twelve men—besides the drawing back of the empty wagons, which had been tipped, to the spot where they had been previously filled— when the number of hours actually worked con- sisted of ten; and when the length of the lead was forty chains, or half a mile. This being the aver- age, taken from the quantity of work done by one hundred and eight men, and twenty horses, with forty wagons, working for eight hours. TABLE 4. Showing the results of a series of experiments, made in order to find the number of wagons which could be removed from cutting to embank- ment, in a given time, on the Birmingham and Gloucester Railway, upon the second extension of the Eckington contract, in May 1839.” * The experiments given in this, and the preceding tables, refer to a single set of wagons only. There were generally three sets working per day; so that the results given in the tables, when multiplied by three, will give the total quantity of work done. It was impossible to make correct observations upon three sets of wagons, at the sametime, or we would have preferred doing so. ExPERIMENTs witH ExPERIMENTS UPON THE BIRMINGHAM AND GLOUCESTER RAILWAY, ON THE SECOND EXTENSION OF ECKING- TON CONTRACT. ** | No. of No. of | No. of | No. of |** wagons of the REMARK Nos. working|_*.* horses wagons hours lead in EMARKS. in a se. working-working: tipped. |worked. jºins. l 4 12 2 59 10 20 The average time W. * O 2 | 8 24 4 119 || 10 | 20 |M|...”.f.". º Ul]]- t CTUITIle (i. eIOlſ)- 3 || 6 18 3 89 || 10 | 20 ||.."...”. nutes. 4 6 18 3 88 10 20 All things connected with these experiments, were the same as those mentioned under the head of the second table; except that the material excavated was sand, and each wagon when heaped contained 68.10 cubic feet. Aecording to this table, the quantity of work done by two horses, four wagons, and twelve men, working ten hours upon a quarter of a mile lead, was equal to 59.16 wagon-loads excavated, filled, removed to embankment, and tipped; besides the bringing back of the empty contRACTORs’ WAGONS. 33 wagons to the filling places: being the average, taken from the quantity of work performed by seventy-two men, and twelve horses, with twenty- four wagons, when working for ten hours; as shown by an examination of the table. The experiments upon the Great Western Railway given in the first table, were inserted in order that a comparison might be afforded of the horse power to be deduced from them hereafter, and that deduced from the experiment we have made upon the friction, due to the ordinary wagons and roads used by contractors; for, as we have deduced the horse power from the amount of friction incident upon the loads, we considered, that the deductions arrived at on that head, would be rendered more conclusive, if corroborated by similar results upon a railway perfectly formed ; where the amount of friction is more accurately and generally known. There was another inducement also for giving them, viz. to show by facts, that the opinion of its being an impossibility to remove from cutting to embank- ment an equal number of wagon-loads, by the same force of men and horses in the same time, and over the same length of lead, whether of stiff or loose soil—of clay or gravel—is an evident fallacy, when referred to the mode of excavation adopted on railways. That the above mentioned 34 EXPERIMENTS WITIT opinion is incorrect, can be easily proved to the practical man as follows:— In the first place, it will be granted by him, that it is quite as difficult to fill gravel into a wagon, as clay or chalk, when once it is stocked * or loosened; and therefore, the only possible way in which the stiffness of a soil can affect the pro- gress of any earthwork, is, by its rendering it necessary to place an eatra getter to every two wagons; which in itself would be, at farthest, a question of earpenditure, not of ea pedition. But that such a necessity never arises, is a point-blank refutation of the opinion ; for when the soil is so stiff, as that the usual number of getters are un- able to loosen it fast enough for the fillers, all practical men have recourse to blasting with gun- powder, as in quarrying stone, rather than add an extra getter; for the plain reason, that they find it the most expeditious means of loosening a large quantity of material at once, and also much cheaper, when the soil will admit of it, than em- ploying getters at all. As for ourselves, we never could see the neces- sity of putting on extra getters; for in general, the stiffer the soil, the greater is the quantity of it that can be brought down by the getter at each fall; as he is enabled to stock much farther in than he * Wide Appendix, Note 11. CONTRACTORS’ WAGONS. 35 can do when the stratum is friable. For instance, stiff clay, or chalk, can be stocked much farther in than gravel, or sand ; and consequently, a much larger quantity becomes loosened when the falls take place; although the frequency of the falls in the two latter mentioned strata, compensates for, and renders equal, the effect in both cases; which would otherwise be different, in consequence of the difference in the quantity of material that would have descended at each time, when the falls occurred. Finally, as regards the compara- tive facility of tipping; when the bumpers” are properly secured, against which the wagons are precipitated at the head of the embankment, no soil, unless it consists of a perfect puddle, (which is an unfrequent exception—the pons asinorum of railway contractors,) will require removal out of the wagons with the spade. We have made these preparatory remarks in order to render the subsequent investigation plainer. SECTION III. Analysis of the eaperiments given in the previous º section. From the experiments detailed in the previous section, we have been enabled to determine the * Wide Appendix, Note 12. 36 ANALY SIS OF constants, upon which the fundamental investiga- tions of the inquiry are founded ; these—as we have mentioned before — are, the time which elapses during each trip made by the horses and wagons, from the face of the cutting—where they are filled—to the head of the embankment—where they are tipped—including the drawing back of the empty wagons into the cutting, and the time required for filling and tipping the wagons. From these constants, the total number of wa- gon-loads that can be removed, from cutting to embankment, in a given time, by a given force, and upon a given lead, can be easily obtained; provided the relation between the time spent in performing these operations and the length of the lead, can be arrived at. In the present section, we have succeeded in determining the above-mentioned points, as the following investigation shows. Since, from the experiments contained in the first table, we have found that 27.66 wagon- loads of material were tipped from four wagons, in eight hours, with their proper complement of men and horses; we have gº 27.66 –H–6.91 for the number of trips which the wagons made —from the face of the cutting loaded to the head of the embankment, and back from the head THE EXPERIMENTS. 37 of the embankment empty to the face of the cutting again—during eight hours ; and further we have 8 × 60 480 sºmeº = 69.47 6.9 IT 6.91 6 minutes, for the time consumed in each trip ; when the lead was sixty chains, or three quarters of a mile in length. From the second table, we find, that with the same number of wagons, 34.80 wagon-loads were tipped over the head of the embankment, by the same processes as mentioned above ; the number of hours actually worked being eight; and the length of the lead forty chains, or quarter of a mile; hence 34.80 tº = 8.70 4 gives the number of trips made; and again we have 8 × 60 480 sió-sid=55.17 minutes, for the time spent in each trip, when the length of the lead was half a mile. We find, from the results afforded by the third table of experiments, that 43.60 wagon-loads of soil, was the number removed from cutting to em- bankment by means of four wagons, with their 38 A NALY SIS OF proper complement of men and horses, when worked for ten hours consecutively, upon a lead half a mile long; hence 43.60 * "YY = 10.90 4 0.9 gives the number of trips made during that time, upon that length of lead ; and 10 × 60 600 = 55.04 IO.90T TO.90 minutes, was the time spent in each trip. Upon reference to the fourth table, it will be seen, that 59.16 wagon-loads of material were removed from cutting to embankment, in ten hours, upon a length of lead equal to twenty chains, or quarter of a mile long ; hence we have *10–14.79 4 for the number of trips made during that time, and 10 × 60 600 I.1.79- fº-40.56 minutes, the time elapsed, from when the wagons left the gullet” loaded, until they returned empty. Having now found the total number of minutes spent in each trip, which the wagons made from * Wide Appendix, Note 14. THE EXPERIMENTS. 39 the cutting to the head of the embankment loaded, and back empty, upon different lengths of lead; the certain portion of that time which it took to fill, remove to, and from the cutting to the em- bankment, and that portion of it spent in tipping them, can be found as follows:— We have seen, that the sum of the times spent in the three separate operations of filling, remov- ing, and tipping the wagons, as deduced from the second and third tables, where the lengths of the leads were the same, (being half a mile long), amounted to 55.17, and 55.04 minutes, respec- tively; taking the average of these, we have *** sºlo or say in round numbers fifty-five minutes, as the time elapsed during the operations of filling, re- moving, and tipping, collectively. The sum of the times required to perform the same operations, as deduced from the first table, where the length of the lead is stated to be three quarters of a mile, amounted to 69.47 minutes; hence we have 69.47—55= 14.47 minutes, for the difference between the time re- quired for filling, removing, tipping, and bring- ing back a set of wagons upon a lead three quar- ters of a mile long ; and the time required for filling, removing, tipping, and bringing back a 40 AN AL YSIS OF set of wagons upon a lead half a mile long. This difference, viz., 14.47 minutes, is evidently the time which elapsed, while the horses were drawing the loaded and empty wagons, backwards and for- wards over a quarter of a mile; or in fact, the difference of time answering to the difference in the lengths of the leads. Again, we find, from the results of the fourth table, that 40.56 minutes elapsed, while the wagons were being filled, removed, tipped, and brought back, when the length of the lead was one Quarter of a mile; and hence we have, by a similar process, 55—40.56= 14.44, as the number of minutes spent, in drawing the wagons backwards and forwards over a quarter of a mile only—exclusive of filling and tipping for the same reasons as stated above. As the lead given in the first table was the longest, and the observations made upon it were consequently less liable to be affected by any minute errors, arising from slight interruptions in the progress of the trains; which may sometimes happen when the length of the lead does not ex- ceed a quarter of a mile; we have taken the result given by the comparison of the first table with the second and third, viz., 14.47 minutes, as the constant for the time, in which a train of earth wagons" can be drawn backwards, and forwards THE EXPERIMIENTS. 41 upon a lead, the length of which is a quarter of a mile; by means of horse power, as ordinarily applied in the execution of earthwork upon rail- ways. This shows that the average speed of transit rates at 2.40 miles per hour. We will now proceed to find the time spent in tipping each wagon, after having arrived at the siding, close by the head of the embankment. Upon reference to the first table, we find, that the time elapsed, from when the wagons left the place of excavation loaded, until they returned empty, (including the tipping), averaged, by actual ob- servation, fifty minutes and a half, when the lead was three quarters of a mile long; and as, accord- ing to the rate of speed established above, 14.47 × 3–43.41 minutes, must have been the time spent in mo- tion; we have 50.50—43.41=7.09, the number of minutes required for tipping the wagons; or, as in such a case as this (where the wagons were tipped sideways off the permanent road), any number can be emptied simultaneously, in the same space of time as a single wagon can be emptied; we have 7.09 minutes, as the time that is required for tipping one wagon also. Upon reference to the second and third tables, where the lengths of the leads were the same, we find that the average of the time spent, from when D 42 AN AI.YSIS OF the wagons left the gullet loaded, until they re- turned empty, was thirty-six minutes; and as the time spent in motion—from what we have seen before—must have been **- 14.47 × 2–28.94 minutes; we have 36–28.94= 7.06 minutes for the time consumed in tipping the wagons; or, as the time required for tipping any set of wagons is the same as the time required for tipping one—provided it does not numerically exceed the shunt or sperm roads, which in these instances they did not—we have 7.06 minutes, for the time required for tipping a single wagon also. In the fourth table we find, that twenty-one-and- a-half minutes elapsed, from the time the wagons left the cutting loaded, until they returned empty, the length of the lead being a quarter of a mile : and as the time spent in motion must have been 14.47 minutes, we have 21.5—14.47 = 7.03 minutes for the time which elapsed while the wagons were being tipped; or the time that would have been spent in tipping a single wagon, as the number of shunt roads were not less than the number of wagons in each set. Now, if the average of the results, afforded by the seventeen experiments given in the tables, is taken upon this point; it will be seen, that the THE EXPERIMENTS. 43 time required for tipping any set of wagons—what- ever may be the number it contains, when the breadth of the tip is unlimited—or, the time re- quired for tipping any set of wagons, which does not numerically eaceed the number of shunt roads placed on the head of an embankment, when the breadth of the embankment is limited, as on railways—as also, the time required for tip- ping a single wagon, in any case; amounts to 7.07 minutes. With regard to the time required for filling the wagons, it is evident, whether a set contains two or twenty, or any other number—provided each set is worked with its proper compliment of men— that the time spent in the operation will be the same in all cases; because, when a set of wagons is brought into a cutting, the men appointed for the purpose commence filling all the wagons in it at once ; so that, whether a cutting is suffici- ently extensive to contain a set consisting of two wagons, or twenty, the time in which every set can be filled will always amount to the same ; hence, we have for the time required to fill any number of wagons, working together in the same set—from the results of the first table— 69.47—(43.41.--7.09)= 18.97 minutes. By reference to the results of the second and third tables—where the time spent in loading, re- D 2 44 AN AI. Y SIS OF moving, bringing back, and tipping the wagons, was fifty-five minutes—we have, by a process similar to the above, 55—G28.94.--7.06)= 19 minutes, for the time spent in filling the wagons; or, from what we have said before, that which would be required for filling any set of Wagons. From the results of the fourth table, we find that the filling and removing backwards and for- wards, besides the tipping, took 40.56 minutes; therefore—by the same reasoning as before, and a similar process—we have, 40.56–014.47.--7.03)= 19.06 minutes, for the time required to fill the wagons; or the time required for filling any set of wagons also ; allowing it to consist of any number what- soever, which the cutting may be extensive enough to contain. Taking the average of the results thus arrived at, we have nineteen minutes, as a constant quantity; denoting the time which is required for filling a set of wagons, of whatsoever number it may consist. Now, these two quantities being always con- stant, whatever may be the length of the lead; their sum, 26.06 minutes, will also become a con- stänt in every calculation, and will represent the sum of the times required for filling, and tipping any single set of wagons. In the method of cal- 2 THE EXPERIMENTS. 45 culation which we have adopted, the quantity becomes the first term of an arithmetical pro- gression, by the reduction of which we have obtained—as will be shown in the following sec- tion—two general formulae; by means of which, the number of wagon-loads that can be removed from cutting to embankment—by a given force, and in a given time, upon any length of lead, variable or constant—can be computed; when the breadth of the head of the embankment is unlimited, (as in tipping to spoil,”) or when the number in each set does not exceed the number of shunt roadst placed at the tip. SECTION IV. Investigation of the fundamental formulae, with a fen, practical applications of them. It is evident from what has been stated before, that the results of any calculations, upon the quantity of material that can be removed in a given time, (according to the common system,) must depend entirely upon the length of the lead—varying when it varies; or, in other words, that they must vary with the amount of time required to remove the wagons from cutting to embankment; because we have seen, that the * Wide Appendix. Note 15. + Wide Appendix, Note 17. 46 INVESTIGATION OF time spent in the operations of tipping * and filling will be always the same, although the length of the leads may vary ad infinitum. Therefore, if the rate of speed or progression, at which the earth can be removed from cutting to embankment, has once been accurately determined—which it is believed we have succeeded in doing in the last section—it is evident we can have recourse to any theoretical principles which embrace variable quantities; and which can be successfully applied to the different lengths of lead which occur, in the formation of cuttings and embankments. The principles upon which the formulae in the present instance are founded, are those which belong to thearithmetical series; it having appeared to us to be the most simple, and at the same time so well adapted for practical purposes, that there was no sound reason for having recourse to any of the higher, or more difficult departments of science. To save the reader the trouble of referring to works on Algebra, the following compendious analysis of the formulae which have been made use of, is given. In any case where quantities increase, or de- crease by a constant difference, it is evident that * It ought to be borne in mind, that what we have said here, with respect to tipping, holds good, only, when the breadth of the head of the embankment is unlimited. It will be shown hereafter, that when the latter is limited, it affects the quantity of work done, jointly, with the length of the lead. FUNDAMENTAL FORMULAF, 47 they come under the same form as the common arithmetical progressions. 1. 2. 3. 4. 5. &c. or H. 3. 5. 7. 9. &c. Therefore if a, represent the first term in the series, and b, the quantity by which the terms in- crease, we shall have : a, a-H b, a-H2b, a-H3b, &c., for the resulting progression. Or, if a, be the first term, and b, the quantity by which the consecutive terms decrease, then the form of the progression becomes a, a-b, a-2b, a-3b, &c. The sum of any positive series of this form can be found by multiplying the sum of the first and last terms by half the number of terms. For let a-the first term, And b-the common difference, or quantity by which the terms increase or decrease con- secutively, Then, a,-Ha-H b-Ha-H2b-H&c. . . . . . a-H (n—1). b-s, also, a-H (n—1). b+a+(n-2). 5-Ha-H (n-3). b + &c.. . . . a =s; by addition, 2a+(n-1). 6+2a+(n-1). b + &c. to n terms=2 s; therefore, {2a+(n-1). b m.–2s; whence, s=| 2a+(n-1). º ſº -: 48 INVESTIGATION OF Or, s={a-Ha-H (n—1). b). -: o the sum of the first and last terms, multiplied by half the number of terms. If the series be of the decreasing form, b, be- comes negative, and S = {a-a-(n-1)} º + e Upon the principles of these formulae, the sub- sequent calculations have been arranged; and the constants have been reduced so as to answer for computing the effects, at every sixteenth of a mile difference in the lengths of the leads. According to this arrangement, the quantity answering to the first term, (a), is 29.6776 mi- nutes; viz: the sum of the times required for filling and tipping the wagons, together with the time required for drawing them backwards and forwards upon a lead of five chains, or a sixteenth of a mile in length; and the common difference answering to b, for a lead a sixteenth of a mile long, will be 3.6176 minutes; being deduced from the constant for the speed of transit given in the third section; also the number of terms, or the quantity answering to n, will be L T5 2 five chains being the sixteenth of a mile, and L being the length of the lead in chains. FUND AMENTAL FORMUL.AE. 49 From the series resulting from the above ar- rangement, we have been able to give condensed formulae, by means of which, the number of wa- gons that can be removed from cutting to em- bankment, in a given time, and upon any given length of lead, varying from a sixteenth of a mile upwards, can be computed as follows. The expanded form of the series being a, a +b, a +2b, a-H3b-H&c......... a-H (n—1).b, we have in figures, in consequence of the above arrangement, 29.67 +33.29-–36.91 +40.53+ &c.. . . . a+(n-1). 5; and the last term will be the time required for load- ing, removing, tipping, and returning to the cutting with the empty wagons, at any given length of lead. The last term (l) is a-H (n—1) b, or, according to our notation, (l)=29.67+ (#–1) × 3.6176, or (l)=.7235 L-H26.06, the time, in minutes, which will elapse during each trip. This time, it may be perceived, increases directly—and the number of trips inversely—as L *- 5 Now if t is put for the whole time in minutes worked, l for the last term in any series, and N for the total number of wagons working, we shall 50 INVESTIGATION OF have }=the total number of trips made during that time; and this multiplied by the number of wagons working altogether, represented by N. will give, / ! the total number of wagons that can be removed, from cutting to embankment, in a given time. If We put its equivalent for l, we get Nt º- .7235 L-E26.06T Hence, the total number of wagons working, and the time in minutes worked, being given, the to- tal number of wagon-loads removed from cutting to embankment, represented in the last formulae by ar, may be computed by the following practical R.U.L.E. Divide the product of the total number of nya- gons n'orking, and the time in minutes norked, by the sum of three-quarters the length of the lead, and the number truenty-sia, and the result mill be the number of nagon-loads removed from cutting to embankment. - When the lead is increasing regularly and ra- pidly, as is sometimes the case in side-tipping, and in dressing off slopes, the sum of the se- FUNDAMENTAL FOR.MUL.AE. 51 ries must be found; this formula, as we have shown above, is s={ 2a+(n-1).] 4- #; and this, divided by the number of terms, (n) will give the divisor to be used in such case, instead of the last term (l). Therefore, using the same notation as before, the formulae applicable to variable leads will be- COIſle *—= –*——w, or (a+1). n. T y (a+1)T“ ” 2n Jº — 2 Nt (a+l) hence, putting their equivalents for a and l, and reducing, we have M t .3617L-H 27.86 the total number of wagon-loads that can be re- moved from cutting to embankment, in any given time, denoted by t, when the length of the lead varies regularly and rapidly; L being in this for- mula the longest of the variable leads. Hence the following practical RULE. Divide the product of the total number of nagons working, and the time in minutes norked, by the sum of one-third the length of the longest lead, and the number twenty-eight; the result mill be the 52 INVESTIGATION OF number of wagon-loads removed from cutting to embankment, myhen the leads become variable. In order to shew the application of the formulae, and the coincidence of their results with those given by the tables, under similar circumstances, we have inserted a few practical examples, as fol- lows. ExAMPLE 1st. Let it be required to find the number of wagon- loads that can be removed from cutting to em- bankment, by means of four wagons, worked for eight hours consecutively, with their proper com- pliment of men and horses, at the usual rate of speed, when the length of the lead is half a mile P In this, and similar cases, where the length of the lead is constant, the first formula must be re- ferred to, viz.: tºº N t *= .7235L-E26.06 or, as in the present instance, N=4, t=8 x 60, and L=40; by substituting them for their equivalents in the above formula, we shall have 4× (8 × 60) (7255×10) E33.06 −"; * FUND AMENTAL FORMUL, AE. 53 I920 the number of wagon-loads that could be removed from cutting to embankment, under the above cir- cumstances. This result agrees within 10, with the average of those given by the second table; where it will be seen that the conditions were si- milar. ExAMPLE 2nd. Let it be required to find the number of wagon- loads that can be removed from cutting to em- bankment, by means of four wagons, with their proper compliment of men and horses, when worked for ten hours consecutively, at the usual rate of 2.40 miles per hour; the length of the lead being a quarter of a mile? Here, the lead being constant, the first formula is to be likewise used, viz: N t = @ .7235L-E26.06 Tº or, as in the present case, N=4, t= 10 × 60, and L-20 ; by substituting them in the general formula, we shall have 54 INVESTIGATION OF 4x (10x60) **(.7335×20)+26.06; Or, =* =59.21 *F10.53 the number of wagon-loads that would be re- moved from cutting to embankment, under the above circumstances; which shows only a tri- fling difference, with the quantity of work done according to the fourth table, when the length of the lead was also a quarter of a mile. Now, in order to show the application of the second formula, or that for variable leads, we will suppose the following case. ExAMPLE 3rd. Required the number of wagon loads that could be removed from cutting to embankment, by four wagons, with their full compliment of men and horses, when worked for ten hours consecutive- ly; allowing the leads to vary from a sixteenth to three quarters of a mile in length P The leads, in this instance, being variable, the second formula must be applied ; viz: Nt - ?? .3617L-E27.86 Tº or, as in the present case, FUND AMENTAL FORMUL.A. 55 N=4, t= 10 × 60, and L=60, (for in this formula L represents the longest of the variable leads); we shall have, by substitution, 4× (10 × 60 E º' - (.3617 × 60)+27.86 T 2 * _2400 tº Or, ** 19.563 =48.42; the number of wagons that could be removed from cutting to embankment, when the leads vary within the limits prescribed in the above exam- ple. The latter question could also be solved by means of the formula given for constant leads, provided the mean of the variable leads was con- sidered as a constant one; but, in almost every instance, the mean of the leads would contain a thirty-second part of a mile, which would render it necessary to alter the constant decimal multi- plier in the divisor, in order to suit the more minute subdivision of the lead. However, under all circumstances, it has been considered more suitable to the nature of the ques- tion, to give a separate formula for each ; espe- cially as the application in both instances is equally simple, if any thing, more agreeable 56 INVESTIGATION OF with practice in the latter; and besides, exhibits a train of induction more immediately analogous to that upon which the first formula is founded. SECTION V. Containing an investigation of the formulae of limitation, which develope the causes particularly affecting the progress of embankment upon railways. The results of the general investigations con- cluded in the previous section, would, of them- selves, be likely to induce a supposition, to the effect—that the quantity of material which can be removed from cutting to embankment in a given time, is, in all cases as unlimited, as the number of wagons that can be filled in a cutting, in the same time. This is true, only, when the breadth of the tip, or the number of shunt roads that can be fixed upon the head of an embankment, is, practi- cally speaking, also unlimited. But this can seldom be the case upon any description of em- bankment, and never with respect to a railway embankment, the instance of a spoil bank being now and then a solitary exception. Therefore, although a hundred wagons might be filled in some cuttings in nineteen minutes, provided each wagon was worked with its proper complement of FORMUL.AE OF LIMITATION. 57 fillers and getters; yet, if the number of shunt roads was so limited by the breadth of the head of the embankment, as that the number which could be tipped in the same time did not exceed eighteen, (which would be the case on an em- bankment twenty feet high, with slopes of two to one, as will be seen hereafter); in a very short time, the roads on the head of the embankment would become so crowded—with the loaded wagons which remained untipped at the expiration of every nineteen minutes—that it would be finally impossible to tip any at all. Hence, it is evident, that the number of wagons which can be removed from cutting to embankment upon railways, must always depend, upon the number of shunt roads that can be fixed on the head of an embankment; or, which is the same in effect, upon the breadth to which the embankment is limited. Otherwise, and were it not for the above rea- son, that the number of shunt roads upon rail- way embankments is generally limited to sir; the number of wagon-loads that could be tip- ped, would be as numerous as the number of wagons that could be filled in the cutting, from which the material for forming it is supplied; or, in other words, the number of wagon-loads tipped, would bear a direct proportion to the area of the face of the cutting ; an opinion which, upon a superficial glance, would appear feasible enough, E 58 INVESTIGATION OF and which is, we believe, at present very pre- valent. Now, this limit to the number of wagon-loads that can be tipped in a given time, which we have referred to above, may be easily determined, gene- rally, by making use of the constants previously obtained in the third section. For there we have seen, that it takes 7.07 minutes to tip a single wagon from one shunt road; and therefore, 60 7.07 will be the total number of wagon-loads that can be tipped over the head of an embankment, and off a single shunt road, in an hour. Hence, putting R for the number of shunt roads that can be fixed on the head of an embankment, we have 60 Hºx R=w Or, a'=8.48 R ; for the number of wagons which can be tipped off all the shunt roads in an hour. According to this, as the number of wagons which can be tipped, will depend upon the num- ber of shunt roads that can be fixed, on the head of the embankment; and, as this again must depend, upon the breadth of the head of the em- bankment; it follows, that the broader every em- FORMUL.AE OF LIMITATION. 59 bankment can be formed, previous to dressing off the slopes, the greater will be the quantity of material that can be removed to, it in a given time. Now, the breadth to which the head of an em- bankment can be formed, previous to dressing off the slopes, will obviously increase, in all cases, with the height of each embankment, and the rate of inclination to which the sides are to be finally dressed off-—for the following reasons. Almost every material, used in the formation of embankments, will stand at a slope of one-and- a-half to one, at least, when first tipped; some soils may remain only for a week at this rate of inclination, while others will remain so for months; and, in many instances, at a much sharper inclina- tion—according to the state of the weather, and the nature of the material itself—before it slips, or collapses finally, into its natural slope. This is a fact known to every practical man. Therefore, as the average number of embankments are finally dressed off, to flatter inclinations than one-and-a- half to one ; and as, from what we have just stated, they can be generally run out in the first formation, at the latter rate of slope; there will be always an extra width, on both sides of the head of the embankment, besides the thirty feet to which it is to be finally dressed off, which can be made available for fixing shunt roads upon. This extra E 2 60. INVESTIGATION OF width, will be always proportional to the difference between the lengths of the bases of the skypes, due to an inclination of one-and-a-half to one, and that to which the embankment is to be finally formed; and, evidently, depends upon the height and rate of slope, determined on by the engineer. For instance,—in the formation of an embank- ment twenty feet high, and thirty feet wide at top, with inclinations of two to one on both sides—we can at first run it out with inclinations of one-and-a-half to one, as we have stated above; and consequently, the slopes will stand, at first, upon only three quarters of the length of the base upon which they are to stand finally; so that the embankment will thus have an extra width at top, on both sides, equal to one quarter the length of the base, answering to an inclination of two to one. In the present instance, this extra width would be ten feet; the height being twenty feet. If the reader will take the trouble to refer to Plate No. 2, Fig. 3; perhaps we may succeed in giving a clearer elucidation of the point in ques- tion. In this figure, a, b, e, f, represents the cross section of an embankment, as it is to be finally dressed off; the slopes of which, a, e, and b, f, we will suppose, for the sake of illustration, to be tWO to One. FORMUL.AE OF LIMITATION. 61 Also, c, d, g, h, represents the cross section of the same embankment, as it can be originally run out; before the sides are finally dressed off, —with slopes c, g, and d, h, of one-and-a-half to one; where c, a, equal to e, g, and b, d, equal to h, f, represent the whole extra width obtained at top, that may be made available for placing shunt roads upon. In the same manner, if the height of the em- bankment was thirty feet, and the slopes, to which it was finally to be dressed off, were two to one also, we should have the base of each slope sixty feet long ; and consequently, if it was originally run out, with slopes of one-and-a-half to one, we should have an extra width on both sides—in addition to the thirty feet at top—of fifteen feet; or a quarter of the length of the base, answering to an inclination of two to one. Hence; the total width gained at top during the formation, would be thirty feet. From what has been already shewn, it is clearly evident, that the number of shunt roads which can be made available on an embankment, or— which is tantamount in the present case—the number of wagon-loads which can be tipped over any embankment, n'hen the breadth of it is limited, must always depend upon its height, and the rate of inclination given finally to the slopes. But to return to the calculation;– since we have 62 INVESTIGATION OF shown, that the number of wagon-loads which can be tipped, in an hour, off the head of an embankment, is expressed by the general formula a'-8.48 R; and, as we have seen, that the quantity repre- sented by R will vary in every instance, according to the final height and rate of slope peculiar to each embankment ; we will now proceed to determine what value is to be ascribed to it, in those calculations that will be most commonly required. For this purpose, let B represent the breadth of the tip head upon any embankment, and S the space occupied by a single shunt road; then, B s=R will give the number of shunt roads that can be fixed. In this expression, S is equal to eight feet in all cases; so that the numerical relation which the quantity represented by B, bears to the height and rate of slope, to which any particular embankment is to be dressed off, is all that remains to be found; in order to determine the quantity represented by R also numerically. Therefore, as we have shown above, that every embankment can be originally run out with slopes of one-and-a-half to one ; it follows, that tnice the difference between the talus of a slope FORMUL.AE OF LIMITATION. 63 of such an inclination, and that to which the embankment is eventually to be formed, added to thirty feet—the constant width of a finished em- bankment—will give the total breadth, which can be rendered available for fixing shunt roads upon —represented in the latter formula by B. This difference, in any case, is the ratio which the bases of the slopes bear to each other; and, with respect to an embankment with two to one slopes, is expressed by r=.5 h 3 h being put for the height of the embankment, and r for the ratio which exists between the bases of a slope of two to one, and a slope of one- and-a-half to one. Where the slopes are three to one, the expression becomes r= 1.5 h. Where the slopes are four to one, it becomes r=2.5 h; and where the slopes are five to one, it becomes r= 3.5 h; and so on. Hence, when an embankment is to be finally dressed off, to an inclination of two to one at the sides; we shall have, for the total breadth that can be made available for fixing shunt roads upon, B=30+2(.5 h)=30+h. In an embankment, which is to be finally dressed 64 INVESTIGATION OF off to an inclination at the sides, of three to one ; we shall, in a similar way, have B=30+2(1.5 h)=30+3 h. If the slopes of the embankment become four to one, after being finally dressed off; we shall have B=30+2(2.5h)=30+5h. and so on in proportion; so that when we have an embankment with 2. 3. 4. 5 or 6 to 1. &c., the corresponding increase in the available width at top, will be 30–H h, 30+3h, 30+5h, 30+7h, &c.; where the law of increase is evident. Consequently, in the expression B R=: S 5 when it refers to an embankment with two to one slopes, becomes, by substitution, 30–H h R= ‘’YT “. 8 With reference to an embankment which is to be finally dressed off to slopes of three to one, it be- COIſleS 30–4–3h. R= * 5 and so on, the value of R increasing, according to the increase in the height of the embankment, and the length the base of the slopes. Hence we have the following general expres- sion, denoting the number of shunt roads that can FORMUL.AE OF LIMITATION. 65 be fixed on the head of any railway embankment; Viz ;— b-H2rh R="##". b, representing the final breadth at top, to which any embankment is to be formed; h, the height of any embankment; and r, the ratio which exists between the base of a slope of one-and-a-half to one, and that of the slope to which any particular embankment is to be finally dressed off. Now, returning to the general formula, which shows the number of wagon-loads that can be tipped over the head of an embankment in an hour, and substituting in it the equivalent values of R, we shall have, for an embankment with two to one slopes— a' = 8.48 (º) 3 Or, a'= 1.06(30+h). For an embankment with slopes of three to one, we shall have a'-8.48 (30+3h). 8 2 Or, a'- 1.06(30+3h). Where the slopes of an embankment are four to one, we shall have, by the same process, a'-8.48 (º), Or, a'= 1.06(30+5h); and so on, with any other rate of slope, to which the sides of anembankmentare to be dressed off finally. 66 INVESTIGATION OF These formulae, it will be perceived by the reader, are applicable to every description of rail- way embankment, when the height, breadth at top, and rate of inclination given to the sides, are once known ; and may be generally represented by the following formula:— * a'-1.06 (b+2rh); * when a represents the number of wagon-loads that can be tipped over any embankment in an hour; r, the ratio which exists, between the rate of slope, at which such an embankment can be at first run out, and that to which it is to be finally formed ; and h, the height of it. For the sake of illustration, we will now pro- ceed to give a few examples, in finding the num- ber of wagon-loads which can be tipped over the head of an embankment in an hour; and first, * Whether the accuracy of the constant 1.06—which is derived from the time we have given for the tipping of a wagon (viz: 7.07 minutes)—is disputed or not, the general form of this expression holds good. For instance, if we put a, for the number of wagon-loads that can be tipped in an hour, of a single shunt road; then, in general terms, the formula will become (b **). ; and holds equally good, whatever may be the values of the factors that may be found from ex- periment. We have mentioned this, merely to show, that this, and the other formulae, will not be affected in principle ; in any case where a difference of opinion may arise, as to the accuracy of the numerical values given to the factors. FORMUL.AE OF LIMITATION. 67 as we have shown that the results of the calcu- lations, in every instance, will vary proportionally with the quantity represented by (b+2rh); in the general formula, a'-1.06.(b+2rh); we will suppose b to be thirty feet—the width at top given to ordinary railway embankments—the height (h) to be twenty feet; and the slopes to incline at the rate of two to One. Hence, allowing that the embankment can be originally run out with slopes of one-and-a-half to one; the above general formula will become a- 1.06 (30+ 2 × .5 × 20); Ol', a'=53; the total number of wagon-loads that could be tipped, under the above conditions, in an hour. Again, if it were required to find the number of shunt roads, that should be fixed on the head of the embankment, to produce this result; we have the general formula, R_*. _b4-2 rh, TS S ’ which—under the same conditions as we have sup- posed—will, in the present instance, become R_**** h). or R_*.* —the greatest number of shunt roads that could be fixed on the head of such an embankment; and 68 INVESTIGATION OF also, the number necessary to insure fifty-three wagon-loads being tipped over it in an hour. Next let us suppose the case of an embank- ment—fifteen feet high, with slopes of three to one, and thirty feet wide at top—where it is re- quired to determine the number of wagon-loads, that can be tipped over it in an hour. Here the general formula, a'-1.06 (b+2 rh), becomes a'= 1.06 (30+3 h), OT a'—1.06 (30+45),=w=79.50 wagon-loads;–the greatest number that could be tipped off such an embankment, under any cir- Cumstances. The formula for finding the number of shunt roads, that could be fixed upon the head of the embankment, under similar conditions; or the number necessary to produce such a result; would become 30–H3h 8 the greatest number of shunt roads that could be fixed; which in practice would be reduced to nine. In some cases the breadth of the embankments on the Great Western Railway was thirty-eight feet; so that in these instances, we should have wº- 1.06 (38+3h); which—if the other conditions are supposed the same as those mentioned in the first example above, R= =9.33, FORMULAC OF LIMITATION. 69 —would become a'—1.06 (38+20)=61.48; —the greatest number of wagons that could be emptied over the head of the embankmentinan hour. Also, the general formula _ (b+2 rh) R=\ºtº, —for finding the greatest number of shunt roads that could be fixed upon such an embankment— would become R -º-; 25. These two latter calculations show, that 8.48 wagon-loads per hour, could be tipped over some of the embankments upon the Great Western Railway, more, than the number that could be tipped over ordinary railway embankments, under similar circumstances. Thus it is evident, as we have mentioned before, that the quantity of material that can be removed from cutting to embankment upon railways—Or indeed in any system of earthwork, where the breadth of the heads of the embankments are limited—must of necessity depend, upon the heights and rates of slope to which the embank- ments are to be finally formed; and moreover, that the opinion—to the effect, that the size, and facility of working afforded by a cutting, renders the expenditure in time and capital comparatively less—is utterly fallacious. P A RT II. SECTION VI. Containing an inquiry into the effects of the lead, njith the alterations, necessary in the general sys- tem of arranging cuttings and embankments, which are derived from it. HAVING shewn, in the first part of the inquiry, the method of determining the greatest number of shunt roads, that can be fixed upon the head of any embankment during its formation; when it is limited, and the dimensions of its limits given; and also, having given the investigation of the general formulae, for finding the greatest possible number of wagon-loads that can be tipped, in an hour, over such an embankment: we shall now endeavour to determine the effect upon the pro- gress of the works, which is caused by the length of the lead, or distance, between the face of a cut- ting and the head of the embankment formed from it; as also, the total number of sets of wagons, and the number of nagons in each set, that will EFFECTS OF THE LEAD. 7I be necessary to produce the greatest effect, with the greatest possible economy of time and expen- diture. It may be frequently observed, that at certain pe- riods in the progress of every railway embankment, a deficiency in horses and materials is experienced by the contractor; and, that an endeavour is made to compensate for this deficiency, by increasing the usual rate of speed, at which the horses trans- port the material from the cutting to embank- ment. This deficiency, is evidently caused by the length of the lead, or distance, which the horses have to travel over, between the cutting and embankment;-which increases as the work pro- gresses. For when the lead exceeds a certain length, the time that elapses while the horses are going to, and returning from, the tip, will become greater, than the time required for filling a set of wagons; so that the wagons cannot be removed and brought back fast enough, to prevent a certain portion of time being lost by the fillers and getters in the cutting. This loss of time must be a serious item in the expenditure of the contractor; who may have to pay, perhaps, a hundred men for a whole day's work; when, perhaps, five or ten minutes at the expiration of every nineteen (the time re- quired for filling a set of wagons,) throughout the day, are utterly profitless—in consequence of 72 INQUIRY INTO THE the delay in the arrival of the wagons, as the lead becomes longer. Therefore, in order to insure such two impor- tant components in the arrangement of a work, as economy and speed, it is well worthy the atten- tion of practical men, to determine the number of sets of nagons, and the number of nagons in each set, which shall be necessary to keep the getters and fillers in the cutting—as also the men sta- tioned on the head of the embankment—constantly employed. To insure this, it is evident, that a certain proportion—between the length of the lead, and the number of sets of wagons—must be previ- ously fixed upon. This proportion—between the length of the lead, and the number of sets of wagons rendered necessary by it—has never been properly defined in any one instance ; and has been mostly, altogether overlooked, in the general arrangement; so that contractors—by not foreseeing the neces- sity of providing an extra quantity of materials and horses, as the length of the lead increases, until it is too late—invariably experience a defici- ency of the means, required to carry on their works with that uniform vigour, which they and their employers were previously led to expect. But, even allowing that a contractor does apprehend a deficiency, in horses or materials; which is a very rare occurrence—he never imagines, that the defi- EFFECTS OF THE LEAD. 73 ciency will be experienced suddenly; nor more- over, when it does arise, has he any means of calculating the extent of it, and the exact extra sup- ply that will counteract it, so as to ensure his horses from being over-worked, and himself from unne- cessary expenditure. Now to remedy these defects, it is evident, that the increase in the number of sets of wagons must take place, at those lengths of the lead, in drawing any set of wagons over which, the same time would be spent, as in filling them ; and also, that the number of wagons in each set, should be such, as that the time consumed in tipping, and filling them be the same ; or, as these times are constant, that the number of wagons in each set, must vary with the breadth at which the embank- ment can be run out in the original formation; for the following reasons. First,--as each set of wagons is tipped, another set must be ready at hand to take its place imme- diately, at the head of the embankment, in order to prevent the men stationed there losing any time. Secondly,–when each set of wagons is filled, another set of empty ones must be likewise ready at the face of the cutting. Now, to effect these arrangements, it is ob- viously necessary that each set of wagons, should contain such a number as can be filled and tipped F 74 INQUIRY INTO THE in the same time; and also, that the number of sets be so proportioned to the length of the lead, as will allow of their following each other in regular order; from cutting to embankment, at cer- tain intervals of time, these intervals being deter- mined by the number of minutes spent in filling each set separately. Where this disposition is not adhered to, the getters and fillers in the cutting must remain idle, after filling each set; while they await the return of the set which was being tipped, during the time they were employed in filling. The methods by which these arrangements can be secured, we shall now proceed to investigate. As the time required for filling any set of wagons—whether it consists of one or twenty, or any other ascribable number which a cutting can contain—will be in all cases nineteen minutes, pro- vided each set is worked with its proper comple- ment of getters and fillers; it follows, that when the lead increases to such a length, as that the time spent in drawing the wagons over it begins to exceed nineteen minutes, two additional sets must be set on, besides the two constantly em- ployed at the head of the embankment, and the face of the cutting. These additional sets, being the two going backwards and forwards between the cutting and embankment, during the time the wagons are being filled and tipped; and so ar- EFFECTS OF THE LEAD. 75 ranged, that they shall arrive at their respective destinations at the expiration of that time. The exact length of the lead at which these ad- ditional sets are required, is every five sixteenths of a mile. For at the rate of speed we have es- tablished in the third section—viz. 2.40 miles per hour—18.05 minutes are spent in drawing the wagons such a distance; and this period of time comes nearest to nineteen minutes, the time re- quired for filling them. Therefore, if we put L for the length of the lead in chains, we shall have L 25- the number of additional sets of wagons required to supply any lead in one direction; or the number of sets travelling constantly between the face of the cutting, and the head of the embankment. But while this number of sets is proceeding onnards to- wards the tip, an equal number must be returning in the contrary direction : consequently, we have 2L , -35°n. for the number of sets constantly in motion, to and from the tip and face of the cutting; and this number, in addition to the two sets that remain stationary, while all the others are progressing— one at the tip, and the other at the cutting, for the purpose of being filled and emptied ;-gives 70), F 2 7t; INQUIRY INTO THE #+2=w for the total number of sets of wagons that must be constantly at work on any length of lead, in order to insure the greatest expedition and eco- nomy. We may affirm, without fear of contradiction, that this order in the sets of wagons has never been exactly adhered to ; both because it was never accurately defined, and because contractors Have seldom or never at their disposal, a sufficient number of wagons to put it into practice, at the time the emergency occurs. However, the atten- tive reader will at once perceive, that the foregoing induction leads to the irresistible conclusion, that such an order and disposition of the sets of wagons are palpably indispensable, before it can be hoped to attain to the two most desirable ob- jects in the arrangement of all works ;-viz : economy and expedition. Only one more point remains for us to investi- gate, and then the development of the more prominent features of the inquiry may be con- sidered as complete. This is, the determination of the number of wagons of which each set ought to be composed. From what has been previously discussed, it is obvious, that each set must be comprised of such a number of wagons, as can be tipped and filled EFFECTS OF THE LEAD. 77 in equal portions of time; otherwise, the order, and due succession in the progress of each set— proved to be so indispensable—would be inter- rupted. Now, the number of wagons in each set, will depend solely upon the breadth of the head of the embankment; or—which is the same in effect—upon the number of shunt roads that can be fixed on it; because the number that can be filled in any cutting, will always exceed the number that can be tipped;” and for this reason, as we have explained before, cannot in any way affect either the progress or arrangements of the works. Hence, let t, represent the time required for filling a set of wagons,—t, the time spent in tipp- ing a single wagon, R, the number of shunt roads fixed on the head of any embankment— and, n, the number of wagons contained in each set; then, in order to prevent more time being spent in tipping any set of wagons, than in filling them, we must have, 7?, it t r—X R, t for the number of wagons in each set; or, as we * This will hold good in every case, except when the mate- rial taken out of the cutting is led to spoil; in which instance, the available breadth of tip, is almost universally unlimited; and, consequently, the number of wagons that can be tipped, will be entirely dependant upon the area of the cutting. 78 NUMBER OF WA G ONS have seen before that the time required to fill a set of wagons, (t), is nineteen minutes, and the time for tipping a single wagon (t'), is 7.07 minutes; we must have, 19 === XR, "=Hdi X Or, m=2.68 R , for the number of wagons required in each set, answering to any breadth on the head of an em- bankment. Or, if we exclude the constant values which we have determined for, t, and t, and put for R, the equivalent which has been given for it— in terms of the breadth, height, and rate of slope of an embankment—in section the fifth of the first part of the inquiry; we shall have, t b-H2rh) 7) E –F– X (ºr, 5 _bt+2r ht Or, n=–sp- for a general expression, denoting the number of wagons that ought to compose each set, upon every embankment: where r, represents the ratio be- tween the basis of a slope of one-and-a-half to one, and that to which any embankment is to be dressed off; h, the height of any embankment; and s, the space occupied by a single shunt road. By applying the constants we have given, the formula—when used for finding the number of IN EACH SET. 79 wagons required in each set, upon any railway embankment—will become n=10.09-H.673 r h; as may be seen, upon reducing the general for- mula; when the constants previously determined upon—are substituted for the letters representing them. Now, for the sake of illustration, let it be re- quired to find the number of wagons that each set of wagons ought to contain ; when referred to a railway embankment twenty feet high, and with slopes of two to one. In this instance, r=.5, and h-20; hence, n = 10.09-H.673 r h, becomes, n=10.09-H.673 × .5 × 20 ; Or, m = 16.82. In practice, seventeen wagons, would be the num- ber required in each set, to insure the greatest possible degree of expedition and economy. If a lesser number, comprised each set, the progress of the work would not be so rapid ; and on the other hand, a greater number would cause a loss of the men's time, who were at work in the cut- ting ; because the time spent in tipping, would exceed the time in filling them, and consequently a delay would be experienced in the arrival of 80 NUMBER OF WAGONS the empty sets, after each set was filled in the cutting; as we have explained at the commence- ment of this section. It may be useful to remark, that no alteration in the contractors' roads will be found necessary, whenever the alterations we have alluded to, may be put into practice; with the single exception, that at every twenty-five chains in length of the road, a siding” will be required, in length propor- tional to the number of wagons in each set ; in order to allow the going and returning sets, to pass each other. This alteration, in itself is very simple, although of great importance. For, as we have mentioned before, according to the present system of arrange- ment, three sets of wagons are made to answer every length of lead, from a sixteenth of a mile to two miles; and when the lead exceeds twenty- five chains, the time that it takes to remove the wagons, from cutting to embankment, and back, begins to exceed the time required for filling them : consequently, the getters and fillers lose a portion of time, after each set leaves the cutting, proportional to that excess; and this evil becomes greater as the lead becomes longer; notwithstand- ing the rude attempts that are sometimes made to counteract it, such as increasing the speed of the horses, &c. Moreover, according to the common system, the greater the number of wagons that * Wide Appendix, Note 16. 1 N E A C H SET. 81 can be crammed in one set, into a cutting, the greater, it is supposed, will be the effect; what- ever the breadth of the head of the embankment may be: the consequence of which is, that the head of the embankment is constantly crowded to inconvenience, with the loaded wagons, which cannot be tipped fast enough ; and the return of the empty trains to the cutting, is retarded, far beyond the proper time for their arrival. With regard to the first of these our investi- gations prove—in order to insure a constant supply of wagons, at the cutting, and tip—it is necessary, that the number of sets of wagons should be so proportioned to the length of the lead, as to form a continuous chain of sets, going to, and returning from the tip, at certain exact intervals of time; which intervals are to be deter- mined by the period required to empty a single set over the head of the embankment. With respect to the second point, we have shown, first—that the number of wagons that can be filled in a cutting, has no effect whatever, on the progress of the work; and secondly—that the carrying out of the opinion, in practice, produces a most injurious effect; for it confines the limits of the tip, which if possible ought to be extended ; and is evidently adopted without any reference whatsoever to the form or dimensions of the embankments, upon which, the results of the investigations demonstrate, that the rapidity of progress must entirely depend. 82 INQUIRY INTO THE The previous portion of the inquiry also satisfac- torily illustrates, the hitherto undefinable causes, which produce the anomalies that so frequently occur in the progress of cuttings and embank- ments upon railways; conducted oftentimes by the same individual, and upon principles of ar- rangement exactly identical. Thus, it often occurs, that two embankments are to be formed immediately contiguous to each other, out of the same material; nay, out of the same cutting:—one of them, for instance, may be twenty feet in height, with slopes of three to one; the other only fifteen feet in height, and having slopes of two to one. Under these circumstances, according to the generally received notions respect- ing earthwork, the engineer or contractor, would without hesitation believe, and act upon the be- lief, that the progress in both would be the same; especially if both were supplied with material out of the same cutting. When the works are to be let, and if the contractors who take them are not in partnership, it is ten to one, but the engineer stipulates for—and the contractors bind themselves to—an equal rate of progress in both cases. The works subsequently commence—the arrangements made by each contractor are similar—and we will suppose, the best which obtain amongst prac- tical men; but it is found out too late—perhaps to the utter discomfiture of the engineer's precon- certed arrangements—and in nine cases out of EFFECTS OF THE LEAD. 83 ten, to the irretrievable ruin of one, and the cent- per-centage profit of the other of the contractors— that the formation of the larger of the two em- bankments, progresses at the rate of 238,500 wagon-loads per annum; while the formation of the smaller one, progresses at the rate of only I 19,250 wagon-loads per annum;-allowing 250 working days in the year, and using the formula given in the fifth section, of the first portion of the inquiry.—This may be shewn as follows:— The formula, which gives the number of wa- gons that can be tipped over the head of any embankment in an hour, is a'= 1.06 (b+2 r h); and in the larger of the two embankments sup- posed above, it will become a'= 1.06 (30+2×30); Or, a: = 95.40, the number of wagon-loads that could be tipped per hour ; hence, 95.40 × 10=954 is the number of wagon-loads that could be tipped during a day; and this, further multiplied by two-hundred-and-fifty—the average number of working-days, computed at ten hours each, in a single year—will give 954 × 250=238,500 wagon-loads, for the greatest possible number that can be removed from cutting to embankment 8.4 INQUIRY INTO THE in a year; when the height of the embankment is twenty feet, and the slope three to one. In the case of the smaller embankment, the formula a'= 1.06 (b+2rh), would become a'-1.06 (30+15); as the rate of slope is given at two to one; or, a'=45 × 1.06=47.70. This, multiplied by ten, for the same reasons as mentioned in the calculations referring to the larger embankment, gives 47.70 × 10=477; and hence, multiplying by two hundred and fifty, we have 477 × 250= | 19.250 for the greatest number of wagon-loads that could possibly be tipped, from the smaller embankment, in one year. Thus then, we find, that one of the two con- tractors, is, by a physical impossibility, prevented from keeping pace with the other, or from ful- filling his engagement, and the expectations of the engineers;–what is the consequence? This—that the opening of that portion of the railway, comprising the smaller embankment, —having been promised by the engineer to the directors, to be the first portion ready, turns out eventually to be the last :-but the consequences do not end here ; for, the directors of the rail- EFFECTS OF THE LEAD. 85 way, (relying upon the authority of the engineer,) having made a similar promise to the proprietary, a réaction takes place; the proprietors call the directors to account;-the directors the engineer; —and the engineer the delinquent contractor, and “assistant,” upon whom all the “devilish enginery” native to arbitrary power is brought to bear. The contractor is first fined, next foreclosed,” if the case be one of emergency; and not unfrequently confined, into the bargain, by his creditors. As for the unfortunate “assistant,” he is either compelled to relinquish his office, and ephemeral authority, to the “mens divinior” of some more fortunate aspirant; or else he struggles on, “shorn of his beams,” and anxiously alive to any opportunity which may offer, in order to recover his “clouded reputation.” The individuals who suffer in such a case as this, may in reality, be persons of good capa- city, considerable energy, and in every way meritorious of better deserts; but who, by an unlucky fatality, were placed under the influence of circumstances, which neither the science of a Newton, or the practical experience of a Smeaton, could control. All these arbitrary measures, and others of a * Foreclosing, means, depriving a person of his contract before it is complete, and stopping the percentage upon any monies due to him, for work previously done. 86 INQ UIRY INTO THE \ similar description, which engineers have resorted to—in many instances, with such fatal effects to the welfare of contractors—are founded upon no just principles of theory or practice; and the results of our inquiry demonstrate that it is equally as absurd to attempt pushing the progress of any earthwork, beyond the limits within which it is confined; in consequence of its peculiar form and dimensions, by applying any extra force of men or horses; as it is, to produce a more rapid moral development by the application of brute force. And the idea, that the irregularities we have noticed, arise from the incapa- city, or want of energy, of the persons immediately connected with the direction of the smaller embank- ment, we have just proved to be utterly fallacious; these irregularities being the effect of natural causes, which are beyond the compass of human control. Engineers will at once perceive, from what we have stated, how much the orderly progress of the railways under their charge—the fulfilment of their own expectations, and those of the proprietaries— depend upon a judicious arrangement of the gene- ral features of the embankments and cuttings, at the commencement; and that the arrangement of their estimates, are not, in all instances, to be pro- portioned with regard to time, according to that determined upon for the largest work they may have to execute; for in many cases the formulae EFFECT'S OF THE L E AD. 87 shew, that an embankment of comparatively smaller dimensions, will take the same time for completion as one of larger. In some instances, it may take a longer time. It is to be hoped, if a more intimate knowledge of the principles upon which railway cuttings and embankments ought to be conducted—which it is the object of this treatise to supply—is once con- firmed and acted upon ; that disappointment, un- necessary compulsion, and the individual ruin of contractors, will become much less frequent, than they have been hitherto. SECTION VII. Determining the amount of friction incident upon Contractors’ rails. Having thus far conducted the reader through that portion of the inquiry, which has reference to the mode of arranging and directing the means at present available in the formation of cuttings and embankments; we will now enter upon the only remaining subject, which appears necessary, to render the investigation, sui generis, complete; viz. the determination of the friction incident upon contractors' rails, and from that, the maximum load which a horse is capable of removing. The power which a horse is capable of exerting 88 AM () U NT OF FRICTION in several ways, has been already experimented upon, and detailed in various works upon engi- neering; but we apprehend, that in most of the deductions upon that head, the difference between the resistance of the surfaces upon myhich the loads mere transported, and that upon which the tractive power travelled, was never sufficiently taken into consideration; or, in other words, that no dis- tinction has been made between that portion of the power which is expended in giving motion to the body in which it is situated, and that portion of it which is effective in traction merely ; which has been determined with respect to the locomotive engine, as the friction due to the machinery and the load are separately laid down. When horse power is made use of in transport- ing materials upon common roads, the surface upon which the horse and his load move, opposes exactly the same amount of resistance to both ; but when it is used as the motion power upon canals or railways, especially in the latter, the amount of resistance to both is materially different. The surface upon which the load is moved upon railways, consists of an iron bar, supported throughout upon cross sleepers; whereas the sur- face upon which the horse travels, is seldom, if ever, as uniform or solid as that of the worst parish road; therefore, it follows, as a necessary consequence, that the horse is compelled to exert on CONTRACTORS’ RAILS. 89 a much larger amount of power in moving him- self, than the load, comparatively speaking. We have therefore taken this opportunity, of noting a singular oversight in all the deductions hitherto made upon the power of horses, and the application of them to practice. This oversight consists, in never taking into consideration the va- rious circumstances under which horse power can be made available. For instance, if we assume the constant for horse power as deduced from observations made upon it, when applied upon turnpike roads, for calculating the effect produced by it, upon a rail- way embankment, during its formation, the result of such a calculation would be exceedingly er- roneous. For, in the former, the power expended by a horse in moving himself, is much less than that which he exerts in the latter, because the sur- face which he travels over is harder and more uni- form ; while on the other hand, the surface over which the load is drawn in the latter case, opposes a far greater degree of rigidity than it does in the former. Hence, it is plain, that the same horse, in drawing any load over a turnpike road, can apply a greater portion of his power to it, than he can when drawing it over contractors' rails, during the formation of a railway embankment; but ne- vertheless, that in consequence of the amount of friction being comparatively smaller in the latter, G 90 A MOUNT OF FRICTION as regards the load, he is capable of producing a greater effect. This distinction, between the fric- tion due to the tractive power and the load, in dif- ferent circumstances, we must leave to philosophers to determine. Our investigations refer only to that practically developed upon railways. The mode in which a horse plies himself, in drawing earth wagons from cutting to embank- ment, is altogether peculiar; he makes use of his own weight, in addition to his muscular power, and lunges, as it were, or hangs against the load; whereas, in drawing a load over a common road, the pace at which a horse travels is considerably faster, and his muscular energy is alone employed; except during the time he is starting the load from a state of rest. Whether these remarks upon the subject in hand, will explain satisfactorily enough to the reader, the difference between the results of the experiments given hereafter, and those stated by other authors, we must leave entirely to his pri- vate judgment; merely stating, that from our experience in such matters, we are led to suppose, that a horse, by making use of his own weight, in addition to his muscular energy, is enabled to produce a much greater effect in drawing heavy loads at a slow pace, and upon an inferior sur- face, than he is at a quicker pace, upon a com- paratively good surface; notwithstanding, that he ON CONTRACTORs' RAILS. 91 may be compelled to exert a much more consider- able portion of power, in overcoming his own friction, (if we may use the term). We are fur- ther strengthened in this opinion, by the direct method of experiment we have had recourse to. In all investigations of this description, it will be found, that the most correct conclusions are to be arrived at, by making use of the data afforded by the established practice, although they may widely differ with theory or previous opinions. For neither the one, or the other, can controvert plain and palpable effects; and it is clear, that where men's private interests are concerned, they scarcely ever fail to find out the way of applying the means in their power to the best advantage. With this view, we thought fit to ascertain—first the actual load that was attached to each horse, in the several instances where we were able to make satisfactory observations;–(the results of these we have stated in the second section;)—and se- condly, to determine the friction per ton, from direct experiments upon loaded wagons. Then, having multiplied the constant for the friction per ton, found thus, into the number of tons contained in each horse's load; we adopted the result as the exponent of horse power, when applied in the particular manner of drawing materials from cut- ting to embankment upon railways. The dis- tinction which we have noted before, has not G 2 92 AMOUNT OF FRICTION been attempted; for it would be out of place here, and does not affect calculations, except when the exponent of horse power belonging to one mode of application, is applied to another mode, entirely different. The value which we are about to give, refers only to the mode of application, from which the observations have been taken. The general load, which each horse was found capable of drawing over contractors' rails, has been mentioned in wagons, in the explanatory remarks following each table in the second section, to which we refer the reader. The experiments, upon the friction incident upon contractors’ rails and earth wagons, which we are about to detail, were made upon an in- clined plane that was constructed by the con- tractor, for working the second lift in the cutting at Bredon's Norton, on the Birmingham and Gloucester Railway. This incline afforded an opportunity very rarely to be met with, for ob- taining an accurate estimate of the amount of friction per ton, from what is generally known as the angle of friction. In December 1839, the inclined plane which was at first made use of, in the Bredon's Norton cutting, was taken up, being found insufficient for the advanced state of the work; and another of greater inclination was substituted. The sleepers were well packed, and the rails laid remarkably on CoNTRACTORs' RAILs. 93 well, for a rough incline, consisting of contractors' rails. iº The form of the incline, or rather the longitu- dinal section of the rails, was favourable; inas- much, as it was not likely to give a sudden check, or jolt to the wagons, when entering upon, and leaving it. The longitudinal section of the plane, if exaggerated, would present the following ap- pearance. *. The incline descended from the face of the cut- ting, where the wagons were filled, towards the head of the embankment; and the difference of level between the top and bottom of the plane—or between the points where the loaded wagons were left to their own gravity, and the point where they came to rest upon the level—was at first nine feet. It afterwards increased to nine feet six inches. Experiments were made, while the differences of level were found to be the same as stated above; and we have given the particulars of each in the table hereinafter inserted. The wagons which were used, were of the same description as those generally working upon con- tractors’ rails; and contained each 49.28 cubic 94 AMOUNT OF FRICTION feet of clay, when filled level, and when heaped in a conical form, they contained 65.72 cubic feet. The material with which these wagons were filled, consisted of blue lias shale; twenty-seven cubic feet of which, thrown loosely together, as in the filling of wagons, weighed on an average one ton; so that the quantity of clay comprising each wagon-load, was equal to 2.43 tons. Upon taking the weight of several empty wagons, it was found, that the average weight of a single empty wagon, was exactly one ton; consequently, the weight of each loaded wagon, amounted to 3.43 tons. The number of wagons with which the experi- ments were made, consisted in all cases of twelve; and the formula made use of, for determining the friction, is the same as that given in the Compte de Pambour's treatise upon the Locomotive En- gine, to which we refer the reader for an investi- gation of it. The formula is 2. & F= P a;+a;' ' where F represents the friction due to the whole ImaSS, P the gross weight, and a-Far' the ratio of the friction, or the quantity which, multiplied into the total number of tons, on CoNTRACTORs' RAILS. 95 contained in the wagons and their loads, gives the gross resistance. The following table, contains the results of those experiments which we have selected from several others. EXPERIMENTS UPON THE FRICTION, DUE TO CONTRACTORS' RAILS AND WAGONS, ON THE BREDON'S NORTON IN- CLINED PLANE. MARCH 4, 1839. ta º tº rº, º * g s?: $ $3: 5 § $3 E! & . q-. H cº.: .s a $2 gº 'º - g 8p 3 . ‘5.3 9-4 tº S 3 || 3: ...? § 3 : . 2 ºf 3 ºf ‘g &# ‘S a;: à || 3 ### ; ; #. § 3 E. : : 3.2 87. §§ #3 sp ####: ºf # 2 = a §§ 3.5 REMARKS. 2. g. ; : 33 £3333 & #, 3. * ſº p ..? F; § 5 ##| |####| || 3: 5 ° # #3 g) g-4 $4 * > 0) 9-4 % Theload for each horse, consisted of two wagons. 1 792 9.00 12 92198.40 || 88 25.45 of 1,50 wagons. Theload for each horse, consisted of two wagons. 3 || 792 9.50 12 92198.40 83.37 26.86 The load for each horse, consisted of 1.50 wagons. 4 || 561 9.00 12 92198.40) 62.33 35.54 l Theload for each 2 660 9.20 12 92198.40 71.75 31.22 {; consisted The weather, at the time we undertook the first and third experiments, was fine during several days previous; and the rails, particularly at the time the first was made, were in good order. At the time the second experiment was made, the rails were moist and dirty ;-or what the 96 AMOUNT OF FRICTION workmen term, greasy—the surface of the rails being covered with particles of wet clay, in con- sequence of a large quantity of rain having fallen during the previous days; although the weather was tolerably fine while the experiments were being made. The weather was exceedingly wet at the time the fourth experiment was made, and the stratum under the sleepers consisted of a perfect puddle; so much so, that the surfaces of the rails were coated with an eighth of an inch of Saturated clay. The friction was so great, when this, and the second experiment were made, that it required two horses to draw every three wagons, after de- scending the plane. Now in order to show the manner, in which the formula we have adopted, has been applied; we have given, as follows, the calculation of the amount of friction per ton; having assumed the data, afforded by the first experiment in the table. Upon an inspection of the first experiment mentioned in the table, we find that twelve loaded wagons, when left to their own gravity at the top of the incline, ran forward seven hundred and ninety-two feet, or twelve chains, from the point where they were first set in motion, until they came to rest; and that the difference of level be- ON CONTRACTORS’ RAILS. 97 tween the starting and resting points, was nine feet. Hence, applying the formula, 2. – P wº-Faº’ we find, P=41.16 tons, or P=9219840lbs. ; and, 2=9 feet; also, ac-Ha!-792 feet. Hence, — — —”--- - a-Ha' T. 792 T 88° the ratio of the friction; and therefore, substi- tuting these values in the original formula, we have I F= 92198.40 5 X as Ol' E=1047.70 lbs., the gross resistance due to the friction. Hence, 1947.79–25.45lbs. 41.16 is the amount of friction per ton upon the gross load. In this manner the value of F has been calcu- lated in the preceding table, and placed opposite each experiment. Several other experiments were made, besides those given in the table; but they always varied in result between the first and fourth ;-the ave- 98 AMOUNT OF FRICTION rage, however, agreeing more nearly with the first. From the results of the four experiments detailed in the table, we would prefer adopting those afforded by the first; viz. 25.45lbs. perton, as the average amount of friction upon contractors’ rails, during fine weather; and 31.22lbs. per ton, as the average amount during wet weather, or when the rails are in bad order for working over. Our reason for this preference, is, that contrac- tors' rails are generally fixed very loosely, when compared with a perfect railway, and are not adapted for a greater speed than the ordinary rate which a horse performs in walking ; so that when wagons are allowed to run down an inclined plane, constructed with these rails, and in the usual manner, a considerable jolting and swerving takes place; resulting jointly, from the inequality of the levels, and the crookedness of the roads. On the other hand, when the wagons are drawn on these rails, at the ordinary rate at which horses travel—viz. 2.40 miles per hour—and on a level, the swerving and jolting ceases altogether; and consequently, the amount of friction is lessened beyond the amounts mentioned in the table, pro- vided the roads are laid tolerably level, and the junctions of the rails are even. However, when the horses are worked at a smart trot, the results in the table will apply exactly, according to the different states of the ON CONTRACTORs' RAILs. 99 weather; but in consequence of the reasons stated above—when the ordinary pace is adhered to—we would recommend the two lowest results; (for they were obtained when the rails were in good order, and under circumstances in which the results were least likely to be affected by the jolting ;) viz. 25.45lbs. per ton, in fine weather, and 31.221bs. per ton, when the weather is unſa- vourable. Now, comparing the results given in the table for the value of F, with the values ascribed to it generally, with reference to a perfect railway; and also comparing the number of wagons which a horse is able to draw generally on contractors' rails, (which consist of two,) with the number which he is able to draw over a perfect railway, (which, according to the experiments made upon the Great Western Railway, we find to be four;) an estimate of the power which a single horse is ca- pable of exerting, when employed in the removal of soil, from cutting to embankment, can be arrived at—sufficiently accurate, we hope, for our present purpose; and also an estimate of the number of wagons of which a fair load for a horse ought to consist; and finally, the number of horses required to execute any earthwork, where the length of the lead is given. It will be seen, upon reference to the explanatory remarks under the first table, given in the second 100 AMOUNT OF FRICTION section, that each of the wagons which were work- ing upon the Great Western Railway, when the observations were made, contained eighty-one cubic feet of gravel—that each empty wagon weighed 1.30 tons—and that one horse drew four of them up an ascent of four feet, six inches, per mile. Now, as twenty-three-and-a-half cubic feet of gravel weigh one ton, and each wagon contained 81 cubic feet, when heaped, (as they were when the observations were taken,) we have, 81 23.5 tons, for the load of each wagon ; and, adding 1.30 tons, for the weight of the wagon itself, we have, = 3.44 3.44-H 1.30=4.47 tons, for the gross weight of one loaded wagon; hence, 4.47 × 4= 18.96, say, nineteen—tons was the total weight drawn by a single horse : therefore, assuming eight pounds per ton, as the average amount of friction I upon a perfect railway, and Hää of the gross weight, as the quantity due to the resistance of gravity, upon a gradient rising four feet six inches per mile ; we shall have 19x8–H36.27 – 188.271bs, for the power exerted by a singlehorse; or the maxi- on CoNTRACTORS’ RAILS. 101 mum force which an ordinary horse can apply, in the usual manner observed upon railways; for four hours a day upon a permanent road, when the speed averages at 2.40 miles per hour, without being over-worked. This result agrees closely with the estimate of a horse's power, given in the appendix to Fredgold's treatise upon cast iron; for, upon reference to that work, we find, that he estimates it at 187.50lbs.; so that the difference between the two, amounts only to .77|bs. If we return to the experiments made upon the Bredon's Norton Contract, on contractors' rails; we shall find, that each wagon contained 65.72 cubic feet of blue lias clay, weighing 2.43 tons, and that the gross weight of one loaded wagon amounted to 3.43 tons; also, that one horse drew two of them on a level for four hours” a day—alter- mately loaded and empty, (when the weather was fine) at the rate of 2.40 miles per hour. Hence, 3.43 × 2–6.86 tons, was the load drawn at each trip, from cutting to embankment, by each horse; consequently, taking the friction per ton, in fine weather, upon con- tractors' rails, at 25.45lbs; we have 25.45× 6.86= 174.68lbs, for the effective power which each horse exerted. * This load was drawn by each horse for four hours a day only, as in the arrangement of the work, loaded and empty wagons were drawn alternately. 102 A MOUNT OF FRI ("I'ION When the weather was unfavourable, we find, upon reference to the table, that the amount of friction per ton, was 31.221bs.; and consequently, we have 31.22 X 5.14= 160.47]bs., for the value of the power which each horse ex- erted during four hours each day. The results of these experiments show, very clearly, that the oversight which we have noted, when remarking upon the usual calculations referring to horse power, does not exist merely in abstract reasoning, but is fully confirmed by practical facts ; for we see, that upon a perfect railway, a horse is capable of exerting an effective tractive power of 188.271bs.; whereas, upon a temporary road, consisting of contractors' rails, laid in the usual manner upon cross sleepers, he can only exert an effective tractive power, amounting to 174.68lbs.; and moreover, that upon the same identical road, when the weather chances to be wet, he is capable of applying only an effective tractive power of 160.47lbs. These differences in the results of experiments, submitted to a similar method of calculation, and similarly conducted, are at once sufficient to arrest the attention of the scientific and practical man ; and will enable him to detect, at a glance, that the conventional assumption of 150 lbs., as the aver- age of effective horse power, is, altogether, an in- on CONTRACTORS’ RAILs. 103 correct datum for founding general calculations upon; especially when referring to railways. They prove, in fact, that for every particular case in which any power is made available, a definite distinction ought to be made, in calculations, be- tween that portion of the power which is expended in giving motion to the body, in which it is situ- ated, and that portion of the power which may be counted effective in the traction of the load, merely. To obtain such a distinction, it is also obvious, that separate experiments are necessary, for every several mode in which the power is brought to bear. For instance, in the three experiments which we have referred to, and from the previous cal- culations, we find, that 188.27–174.68– 13.59 lbs. was the value of the extra amount of power which each horse applied, in moving himself, when drawing upon contractors' rails during fine weather, beyond that which it would be necessary for him to exert upon a perfect railway ; and again, that 174.68—160.47 = 14.21 lbs. was the extra amount of power expended by a single horse in giving motion to him- selſ, when the weather was wet, beyond that which he was compelled to exert during fine wea- ther, upon the same temporary road—the rate of 10 ! AMOUNT OF FRICTION speed amounting to 2.40 miles per hour, and the surface worked over being level. Now, as a perfect railway offers the least possi- ble resistance of any other surface which we know of, both to the body in which the tractive power is situated, and the load it draws; we have as- sumed the value of the horse power deduced from it, as the greatest possible which can be effectually applied under any circumstances, when the horses work day after day. Hence, taking 188.27 lbs., as the maximum effective value of the force that can be rendered available in traction; we will pro- ceed to determine the effective power, which a horse can exert upon contractors' roads, when worked for eight hours consecutively, at the rate of 2.40 miles per hour. First, then, with respect to a perfect railway we find, that the maximum force of traction exerted by each horse, amounted to 188.27 lbs; but that this effort did not continue for more than four hours, the remainder of the time being spent in returning with the empty wagons, from the point where they were tipped, to that where they were filled. Hence, having 188.27 lbs., for the value of the power which a horse exerted, during four hours; it remains only to find the power which he exert- ed, in drawing the empty wagons during the re- maining time; and the mean of the two, will on contRACTORs' RAILS. 105 give the value of the power, which a horse in si- milar circumstances can exert constantly; when worked eight hours a day consecutively, at the rate of 2.40 miles per hour. Now we see, upon reference to the first table, in the second section, that four wagons were affixed to each horse, and that each wagon weighed 1.30 tons; therefore, the total weight which each horse drew, during half the time he was in motion,” amounted to 1.30 × 4=5.20 tons; and the friction to be overcome in drawing this load, down a gradent of four feet six inches per mile, must have been equal to 5.20 5.20x8–Hºa–31.67 lbs.; the value of the effective force, which the horse exerted during four out of the eight hours, he was at work. Taking the mean of these results, we have 109.97 lbs., for the value of the power exerted during eight hours, at the rate of 2.40 miles per hour; which shows, that a horse upon such a sur- face, can remove 263.61 tons, one mile a day, or 13.73 tons, 19.20 miles a day, when he draws the same load constantly; but in the particular instance * The reader should bear in mind, that during half the time a horse is at work upon Railways, he is employed in drawing back the empty wagons, from the tip, to the face of the cutting. H I ()6 AMOUNT OF FRICTION of a railway this is impossible; because, from the necessary order of the works, the same horse is employed, alternately, in drawing loaded and empty wagons: consequently, as we perceive upon re- ference to the third section, that 6.91 trips were made by each horse, upon a length of three quar- ters of a mile, with a quantity of material weigh- ing 18.96 tons; (5.20 tons of which are due to the weight of the empty wagons) we have 13.76 × 6.91 = 95.08 tons, for the neight of material which each horse removed from cutting, to an embankment, three quarters of a mile distant, in eight hours; which is equal to 71.37 tons of material, moved one mile per day; and this is the maximum practical effect, that a single horse can perform upon a perfect railway, when worked in the particular manner we have referred to. By a similar process, we can determine the actual, and efficient power, (practically speaking), which a horse can exert upon contractors' rails dur- ing fine weather; for assuming 188.27 lbs., as the maximum power which he can apply during four hours, at 2.40 miles per hour; we find that upon a temporary road, only 174.68 lbs. of it can be rendered available for drawing the load, the remaining 13.59 lbs. being expended in overcom- ing his own friction—and moreover, that this power was applied only for four hours; conse- on contRACTORs' RAILS. 107 'quently, if we take the mean between this, and the power which he applied in drawing the empty wagons, during the remainder of the time; we shall have the value of the power expended, when we suppose the horse to draw the same load con- stantly, for eight hours a day, at the rate of 2.40 miles per hour. Therefore, as each horse, when the weather was fine, drew two wagons, which, when empty, weighed one ton each, we have 2× 25.45=50.90 lbs., for the value of the power he exerted, during four out of the eight hours; hence, the average power which he exerted for eight hours consecutively, amounted to 112.79 lbs. This would be equal to an effect of 84.67 tons, removed one mile a day, or 4.41 tons removed 19.20 miles a day, if the horse drew the same load constantly, upon a temporary road; but the practical effect produced, in removing material from cutting to embankment, would be quite different; for, upon reference to the third section, we perceive, that 8.70 trips were made by each horse, over a lead half a mile in length, and with a load weighing 4.86 tons.” Hence, 4.86 × 8.70=42.28 tons, * The actual load drawn by each horse, at each trip, was 6.86 tons; the weight of two wagons and their loads—but as the wagons weighed two tons, the quantity of material re- moved by a single horse, from cutting to embankment, at each trip, amounted only to 4.86 tons; as we have stated above. H 2 108 AMOUNT OF FRICTION was the quantity of material removed from cutting to embankment during eight hours, when the length of the lead was half a mile; which is equal to 21.14 tons, removed one mile a day, by each horse. Again, when the weather was wet, we have seen, that 160.47 lbs. was the value of the power which each horse was capable of exerting; there- fore, as this force was exerted for four hours only out of the eight, which were worked; and as every empty wagon weighed one ton, and three were attached to two horses; we shall have 1.5 × 1 = 1.5 tons, for the weight, which each horse drew during the remainder of the time; and 1.5 × 31.22=46.83 lbs., for the value of the effective power. The mean of these, gives 103.65 lbs., for the average power of each horse; which would produce an effect, equal to 63.74 tons of material removed one mile a day, or 3.32 tons removed 19.20 miles per day, when the horse is supposed to draw the same load con- stantly. In the formation of a railway embank- ment, during wet weather, the practical effect pro- duced by a single horse, however, would amount only to 31.66 tons of material, removed from cutting to embankment, over a lead of half a mile long ; or 15.83 tons, removed a distance of one mile.* * This may be proved, by the same reasoning as that in the on contRACTORS’ RAILS. 109 The slightest consideration, on the part of the reader, will show him, that the discrepancy be- tween the quantity of material which ought to be removed—judging from the ponyer which the horse eacerts—and that which he actually removes; arises from a portion of time and power being non-effect- ive, while he is drawing empty wagons: and the quantity of both last, while the horses are being attached, and detached from their loads. These calculations show, that the effective force exerted by each horse, in traction upon a perma- nent road—when the wagons are moved forwards and backwards, loaded and empty, alternately— amounts to 109.97 lbs., if worked at the rate of 2.40 miles per hour. This is equal to an effect of 263.61 tons, removed one mile per day. They also show, that the effective power applied in trac- tion, by a horse on a temporary road, under the same circumstances, in fine weather, amounts to 112.79 lbs.;* which is equal to an effect (allowing 25.45 lbs. per ton for the friction,) of 84.67 tons preceding page; relative to the practical effect produced, when the weather was favourable for working. * It is singular, that the value of the power, should become less upon a permanent road, than on a temporary one. But, perhaps, in calculating the former, no deduction ought to be made for the effect of gravity, upon so slight an incline as 1 for it is likely, that no effectual assistance was af. 1173.3’ forded by it to the horses; although theory alone would lead us to suppose there was. I 10 AMOUNT OF FRICTION removed one mile a day; but that the practical results amount (from the peculiar manner in which horses are worked upon a railway,) only to 71.31 tons, moved one mile a day, in the former instance, and 21.14 tons in the latter. The last may be taken as the average practical effect, produced by a single horse, per diem, on temporary roads; as contractors seldom work during wet weather, except in cases of extreme emergency; and therefore, we have passed over the calculations made for wet weather. From the experiments detailed in the previous part of this section, and the calculations founded upon them, we have been enabled to calculate the load proper for each horse, when employed in re- moving materials, from cutting to embankment, upon railways; according with the different kinds of weather during which the experiments were made: and the method of calculation we have adopted, is as follows. Let P, represent the power of a horse—F, the friction per ton, upon the load which he draws— and W, the weight of a loaded wagon in tons; then it follows, that P FX W is the load proper for each horse, expressed in wagons; and this value of X has been given in the following table. =X on CONTRACTORS’ RAILS. III TABLE, GIVING THE LOAD PROPER FOR A SINGLE HORSE, EXPRESSED IN WAGONS, ACCORDING TO THE STATE OF THE WEATHER. Value of Value of Value of Value of State JF in W in P in P Value | of the REMAwks. lbs. tons. lbs. FX W. of 2% weather. 188.27 * * * 25.45 3.43 |188.27|25.45×3.43 2.09 || Fine, {*...* * 188.27 | 31.22 || 3.43 |188.27|31.22x3.43 | 1.75 | Fine. {*...* 188.27 & g 26.86 3.43 |188.27|26.06x3.43 2.04 || Fine. {*. 188.27 35.54|| 3,43 |188.27|35.54×3.43 | 1.54|| Wet. |{ºn In the above table, the weight of each wagon is taken at 3.43 tons, when loaded; but if wagons, capable of containing a greater quantity of mate- rial than those commonly used by contractors, are at work, the results can be easily arrived at, in a similar manner to that shown by the formulae we have previously given, when once the friction due to them is determined ; which latter will evi- dently vary, according to the construction and dimensions of the wheels upon which they are Supported. \ I 12 SUMMAR Y GF THE SECTION VIII. Containing a summary of the principal formulae and facts, connected with the removal of mate- rial by nagons and horse ponyer—as collected from the foregoing sections—together mith the conclusion of the inquiry into that department. Having now investigated every circumstance, which can affect the formation of cuttings and embankments upon railways; we will make a summary of the principal formulae contained in the previous pages, according to the Order in which they present themselves, previous to closing this inquiry; and also some observations, explana- tory of each, should such appear necessary; to- gether with a table, showing the number of men, horses, and wagons, required in different kinds of weather, and on different lengths of lead, when the breadth of the head of the embankment af- fords room, sufficient to allow of six shunt roads being placed upon it. 1. Upon referring back, we find, that the first for- mula arrived at was one of a general nature, for finding the total number of wagons-full that could be tipped, in a given time, when the length of the lead and the number of wagons working, are given, if the breadth of the head of the embankment is comparatively unlimited; or not narroner, than will FOREGOING SECTIONS. I 13 allow of such a number of shunt roads being fixed upon it, as will enable the men stationed there to tip a set of wagons in the same time, as the men in the cutting can fill a set, consisting of the same number. This formula is —F Ø ! 5 where N represents the number of wagons work- ing, t the time in minutes worked, and l the time which elapses while one set of wagons is being filled, removed, tipped, and brought back, upon any length of lead. This formula is applicable to any mode of transporting materials on a railway, or elsewhere; and the only difficulty in rendering it applicable in any particular case, will be found in determining a correct value for the denominator (l). This value will, of course, vary according to the method of arrangement adopted, and the friction. The latter must be found by direct experiment, where it has not been given before; and the formula, —when referred to the method of arrangement generally followed in the execution of earthwork upon railways—becomes, upon reduction, N t = @ .7235L-E26.06 T’’ where L represents the length of the lead in chains, and a the number of wagons-full tipped 114 SUMMARY OF THE over the head of the embankment, in a given time —denoted by t. We will give the following instance of its ap- plication in railway practice. Suppose a contractor was about to engage to remove from cutting to a spoil bank (when the breadth of tip is unconfined) fifty thousand cubic yards of earth—the length of the lead being half a mile—and that he wished to calculate the num- ber of yards he could transport per diem, by means of fifty wagons, working for ten hours each day; in order that he might regulate his en- gagement as to progress, and estimate the proba- ble expense per yard. By reducing the above formula, or substituting the constants we have given, he would have 50 × 660 e (.7335×40) E33,067" and upon reduction, the value of a will be found equal to 600; therefore, if we assume the contents of each loaded wagons to amount to two-and-a- half cubic yards, the total number of yards re- moved in one day would amount to 1500. Hence, 50.000 #––88; would be the number of days norked, in which he could remove the whole quantity. Having once found the number of working FOREGOING SECTION. II 5 days, he can easily arrive at the net cost per yard, by inquiring the average price of labour in the neighbourhood of the work. If the average amount of a labourer's wages was three shillings a day, and the cost of keeping the horses five shillings per day—materials being at the present market price—then the cost of the above work would average at ninepence per cubic yard; (making allowance for the probable number of days that will turn out wet, in the ratio of one- sixth of the time worked, and for contingencies, &c.)—so that the contractor would be amply re- munerated for risk and trouble, if he undertook to perform the work, at the rate of elevenpence per cubic yard. 2. The next formula which presents itself, is one of the same nature, but having reference to variable leads only; and is 2 N # (a+l) for general application. Here, a, represents the time required for loading, removing, tipping, and returning, with any set of wagons, upon the shortest lead; and l, the time re- Eð, Quired for performing the same operations, upon the longest of the variable leads. This formula will be found useful in all cases, where the lengths of the leads vary, such as in the trimming of slopes, &c.; but as the same remarks 1 16 SUMMARY OF THE and illustrations apply to this, as to the preceding formula, we will pass on to the next: this deter- mines the limit to which the tipping of wagons is restricted, when the breadth of the head of the embankment is limited to a certain number of feet; or rather, when the breadth of it renders it ne- cessary to confine the number of wagons in each set, beyond that which otherwise might be ad- vantageously worked in the cutting. 3. This formula is 8.48 R=a'; a' being the greatest number of wagons that can be possibly tipped in an hour, off a given number of shunt roads, represented by R.; and 8.48 being the number of minutes required for tipping a sin- gle wagon off a single shunt road. This formula affords no particular grounds for remark. 4. The formula, expressing the number of shunt roads, which can be fixed upon the head of an embankment, when the height and rate of slope to which it is to be dressed off, are given, be- comes—for a embankment having two to one slopes— 30+h. 8 5 —for one with slopes of three to one,— R_*. R= For EGOING SECTIONs. I 17 —for one with four to one slopes, _30+5h. – sº- R —or generally,– R_(b+2rh). S R, representing the number of shunt roads; b, the breadth of the embankment; r, the ratio between the bases of a slope of one-and-a-half to one, and that to which the embankment is to be finally dressed off; and h, to the height of the embankment. This formula proves, that the greater the height of the embankment, and the flatter the inclination of its sides, the greater will be the number of shunt roads that can be fixed upon it. This, with regard to the time in which an earthwork can be completed, is exceedingly favourable; because it shows that the magnitude of the work is compensated for, in most instances, by the greater facility of tipping; or, in other words, that the larger the embankment, the greater will be the amount of material removed from cutting to embankment, in a given time; and also, in the formation of small embankments, although they require a lesser quantity of mate- rial in formation, yet that, upon the whole, they cannot be finished in much less time than large OIléS. 5. The next formula, determining the greatest number of wagons that can be tipped, in a given 1 18 SUMMARY OF THE time, during the formation of a railway embank- ment, is one of universal application; for it em- braces every ascribable breadth of tip, when once the ratio of the inclinations of the sides of the embankment is known. The formula is a'= 1.06 (b+2rh); where b and h, represent the final breadth and height of the embankment respectively; and r, the ratio between the bases of a slope of one- and-one-half to one, and that to which the sides of the embankment are to be eventually formed; ar, representing the total number of wagons that can be tipped within an hour. The modifications of this formula, to suit the in- clinations given to the sides of railway embank- ments generally, will be seen upon reference to the investigations under that head, given in the fifth section of the first part of the inquiry. The last factor in this formula evidently increases with the height, and rate of inclination, given to the sides of the embankment. This formula also affords a good opportunity to the engineer, for finding, approximately, the ratio between the cross sectional area of any em- bankment, and the progress which may be ex- pected in its formation; and hence, a rough esti- mate of the cost per yard run, if required. This FOREGOING SEC'PIONS. l 19 is so obvious, that it is unnecessary for us to enter upon it. The preceding formulae comprise every point necessary for calculating the results, which a given force of men and horses is capable of producing, in the execution of cuttings and embankments upon railways, as they are universally applied in the present day; but the remaining formulae will, we trust, convince the practical reader, that two very important and valuable modifications may be made in the present system, tending towards the attainment both of expedition and economy. These modifications consist, in arranging the num- ber of sets of wagons, and the number of nagons in each set, in proportion to the available breadth of the tip, and the length of the lead. The formula, developing the necessity of keeping up a certain proportion between the length of the lead and the number of sets of wagons, is that with which the investigation contained in the second part of the inquiry commences; and the result shows, that at certain lengths of the lead, on all works, a double set of wagons is required; in order to ensure a constant supply at the face of the cutting, and the head of the embankment, and thereby prevent any waste of time in carrying on the works. The latter is of constant occurrence, and altogether unavoidable, in the present system of arrangement; where three sets, at most, are made 120 SUMMARY OF THE to answer for every variety in the lengths of the lead. \ The formula we refer to, is generally 2 L A// — `--2=777": where L, represents the length of the lead; and n", the number of sets of wagons required for executing any work, upon a lead answering to the quantity denoted by L. This formula proves, that the number of sets of wagons, does not, in any instance, depend upon the number that can be filled simultaneously in a cutting; or upon the area of the face of a cutting; but, altogether, upon the length of the lead;—and moreover, that is quite unnecessary, and extrava- gant, to throw out a long gullet, for the purpose of working more than one set at a time in it. Such has been hitherto recommended and adopted, as a part of the arrangement, especially in shallon, cuttings ; but, even before we commenced these investigations, we could never discover any sound reason for doing so. On the contrary, we always found that the general attention being employed, in rendering the greatest possible area of cutting available for filling the wagons, produced an effect quite contrary to that anticipated, both at the face of the cutting. and at the head of the embankment; in consequence of its being impos- FOREGOING SECTIONS. 121 sible to tip the wagons as fast as they were filled, which causes an irregularity and delay, in the ar- rival of the sets at both places. The formula which immediately succeeds the preceding one, determines the number of wagons that ought to comprise each set; and shows, that this number must in all instances depend upon the breadth of the head of the embankment. For general use, it becomes n=-|- × R ; t, representing the time spent in filling a set of wagons, of whatever number it may consist, t', the time spent in tipping a single wagon, and R, the number of shunt roads that can be fixed upon the head of an embankment. The latter varies with the height, and rate of slope, given to any particular embankment; or—which is the same in effect, as we have seen before—with the available breadth of the tip ; and consequently, as t, and tº, are constants; the value of n, or the number of wagons in each set, must vary also, with the available breadth which can be procured, for tip- ping over the head of any embankment. This proves, that the number of wagons in each set, instead of being optional—as generally sup- posed, upon all works—must depend altogether upon the dimensions of the embankment; and moreover, that in all cases, where the number of I 122 SUMMARY OF THE wagons in each set, requires a greater portion of time being spent in tipping, than in filling them; a retardation in the progress of the work, will be the inevitable consequence in the first place; and, in the second, that a much greater expenditure will be incurred—beyond that which would be necessary, if a due proportion was kept up, be- tween the number of wagons in each set, and the breadth of the tip ;-arising from the irregularity in the returns of the empty sets, which causes a loss of the men's time in the cutting. From the manner in which contractors’ roads are laid, the modifications shown by the first of these two formulae, may be brought into practice, simply by increasing the number of sidings, as the length of the lead increases. For, with reference to the first modification, we have seen, that at every twenty-five chains, a double set of wagons is required, in addition to those previously at work; one for the up, and the other for the down line: so that if we suppose the length of the lead to be one hundred chains, there must be six sets constantly in motion;–three loaded, proceeding towards the tip, and three empty, returning from it; besides two sets sta- tionary—one at the tip, and another at the cutting: moreover, that each of the sets in motion, will follow, and pass each other at certain intervals, equal to twenty-five chains; hence, each separate set going to, or returning from the tip, will pass FOREGOING SECTIONS. 123 three others going a contrary way, at distances of twenty-five chains. Consequently, as we know the exact points, at which the sets will pass each other, the necessity of laying a double line of way is easily avoided, by inserting a siding at each of them. The modification shown by the last formula, can be put into practice, without rendering it ne- cessary to make the slightest alteration in the ar- rangement of any of the other materials, except the wagons themselves; because all that is wanted to be known, is the exact breadth of the embank- ment, which can be made available for fixing shunt roads upon. Neither of these arrangements, which the two latter formulae prove to be so eminently advanta- geous, and which can be brought into practice so easily, has ever been attempted as yet. In all the works, which we have had an opportunity of examining, we found that the number of sets of wagons, and the number of wagons in each set, were merely regulated by the number that could be filled at a time in the cutting ; and when filled, that each set was drawn out into a siding, at the end of the cutting, from whence they were removed by the horses which came up with the empty wagons from the tip ; and that, in a similar manner, the empty wagons were brought from the head of the embankment to the cutting; I 2 124 SUMMARY OF THE whether the length of the lead was one mile or two miles—variable, or constant. The inferiority of such a system, when compared with that deve- loped in the latter formulae, is self-evident. Let us suppose an instance, where the length of the lead is an hundred chains. Then, from what we have seen before, all the wagons in the cutting could be filled in nineteen minutes, and would be drawn towards the head of the embankment; but the set coming from the head of the embankment, to occupy their places in the cutting, would only have advanced about half way during that time; consequently, the getters and fillers in the cutting must remain idle, for a considerable time, after the loaded set left, until the empty one arrived. As the length of the lead increases, this evil increases; and can in no possible way be per- fectly avoided, except by such an arrangement of the sets, and number of wagons in each set, as the two latter formulae require. With respect to pro- gress, the evil pointed out is sometimes compen- sated for, in a great measure, by increasing the speed of the horses, which is evidently a most ex- pensive alternative. From the difficulty of prosecuting works suc- cessfully, according to the common arrangements, arises the general disinclination, on the part of contractors, to undertake any work with a long lead; unless they receive a price, highly dispro- portionate to the real difficulty of the case; if the FOREGOING SECTIONS. 125 method of working, and the principles upon which it depends, are duly considered. But, on the other hand, it is evident, that the evils in the present arrangement must remain for a consider- able time, until persons duly qualified to conduct these works upon scientific principles, become numerous enough. This epoch is far distant; for it is a labour of many years—and for which few men are constituted—to become proficient equally in science and practice ; and in this, as in all cases of a similar kind, we must be prepared to witness immense sacrifices, both of power and money, in the attainment of the ultimate object. The last subject which we have entered into, is the friction due to contractors' roads, as now generally used. In the Compte de Pambour's treatise upon the Locomotive Engine, a full in- vestigation has been given of the formula for finding the value of friction, from what is gene- rally called the angle of friction: and this we have adopted, in the investigations under that head; so that it is unnecessary for us to enter into a de- monstration of it here. The formula is F= P : , a +a; P representing the gross weight descending any plane, and riz the height descended, divided by the distance between the points, where the load was first left to its own gravity, at the top of the 126 SUMMARY OF THE plane, and where it came to rest, after having des- cended the plane. The values of 2, and a +a', are to be given in feet. The experiments give * as the ratio of the friction to the load in fine weather, and for I 77.73 the ratio of the friction to the load in wet wea- ther. The great difference of these results, as com- pared with those already given for Permanent lines of Railway,” induced us to undertake several sets of experiments; but none of them differed materially from those given in the table. How- ever, although the apparent difference in the rigidity and evenness, of permanent and contract- ors’ roads, would not, at first sight, lead us to suppose, that the amount of friction upon the latter, was nearly in the ratio of four to one to that on the former; yet,_if we bear in mind, that the greatest load which a single horse was found capable of drawing conveniently, consisted of two loaded wagons, or 6.86 tons, on con- tractors' roads, laid level ; and, of four loaded wagons, or 18.96 tons, on a perfect railway, up an incline of four feet six inches per mile;—the * It is scarcely necessary to remind the reader, that the average amount of friction upon permanent lines of railway, is 81bs. per ton; or # of the gross weight of the load. 9 FOREGOING SECTIONS. 127 fact of such a large amount of friction between the two, is satisfactorily evident, from the difference between the gross loads, which the same power can draw upon each. Hence, for all practical purposes, we are confident, that the values we have determined, for the friction upon contractors' rails, are sufficiently correct. From the results of the observations upon the Great Western Railway, we found that under the circumstances, it was requisite to apply a force of 188.271bs., to overcome the friction due to the load, which each horse was capable of drawing, when worked each day consecutively for eight hours ; and we have, under the head of horse power, stated our reasons for adopting this as the standard estimate, of the maximum power a single horse can exert, when employed in removing soil from cutting to embankment, upon railways, or any other works under similar circumstances. This amount seems large; but when it is con- sidered, that in the particular case of a railway, although each horse draws nearly seven tons from cutting to embankment; yet, he draws no more than about two tons back, from the head of the embankment to the cutting ;-and conse- quently, exerts a power of 188.27 lbs., during only one half of the time he is at work;-the ap- parent excess, in the value of horse power, which we have given, will vanish. At all events, our object upon entering upon this portion of the 128 SUMMARY OF THE inquiry, was, not to determine the power, which is due to a horse, working with an uniform load, for eight hours consecutively; but to determine the maximum power which he can exert, when worked for eight hours, day by day, and in the particular manner, rendered necessary by the mode of forma- tion peculiar to railways; and having determined this, to obtain the load proper for a single horse. The following table gives the number of sets of wagons, the number of wagons in each set, the total number of men, and the total number of horses, which would be required in the formation of an embankment, of the ordinary width at top, twenty feet high, and with slopes of two to one; at any length of lead, varying between 25 and 175 chains ; when the arrangements we have pointed out, are adopted. In the formation of this table, three men are allowed as the full compliment for working each wagon in the cuttings; two men are allowed for attendance upon each set of wagons, from the cutting to the tip, and back; and fifteen men are allowed for attendance at the tip, keeping the roads in repair, and turning the switches, &c. It may be further remarked, that the full com- pliment of horses is allowed for every set, except the one supposed to be employed in the cutting. The set at the head of the embankment is not excepted; because it will give sufficient employ- ment to its own compliment of horses, in drawing FOREGOING SECTIONS. 129 the wagons from the siding, near the head of the embankment, to the tip head. TABLE, SHOWING THE QUANTITY OF LABOUR, AND MATERIALS, REQUISITE FOR WORKING AN EMBANKMENT, 20 FEET HIGH; witH LEADS WARYING FROM TO 1; OF A MILE, WHEN THE SLOPES ARE TWO TO ONE. No. of Total No. of wagons No. of No. of N.F Length of lead. sets of . . . men horses wagons REMARKs. wagons. s. Tequired.required. required 5 º # miles, or In this table, the 25 chains 4 16.82 69 25.23 67.28 calculations are made ſº according to the for- 3. º in the 6th 5 & ection, for the num- # miles, or ; 6 | 16.82 | 73 || 42.05100.92 sº 50 chains. answering to each lead. The results in 15 l Wagons and horses ap- & pear very large, when i; miles, or 8 | 16.82 77 58.87 |134.56 compared with the 75 chains. Common system, where only three sets are 1. il used º; every varia- IOOllies, Ol' tion of lead. But iod chains } 10 16.82 81 75.69 168.20 when the time lost ſº at º trip, according to the latter system 1% miles, or is taken into account, 16 5 * it will be found, that 125 º) 12 | 16.82 85 92.51201.84."...” ranged as in the table, will eventually re- 14 …; quire less expendi- #. *} 14 | 16.82 | 89 109.33 235.48 ture, and be finished CI18,111S, S007.67°. NoTE.—According to the common system of arrangements, where three sets of wagons only are used, the force required at a lead of 1% miles, would be 89 mem, 51 working wagons, and 34 horses; and so on, in all cases, except where a loco- motive engine is used instead of horse power. I 30 SUMMARY OF THE The foregoing table, as we have previously re- marked, is calculated for an embankment twenty feet high, and is given as an illustration of the principles developed in the inquiry, but not as a table answering every variety in the heights of embankment; for the formulae show that in all cases, the tabular numbers will increase or decrease, according as the number of shunt roads, that can be fixed upon the head of the embankment, increases or decreases. For instance, in the case of a spoil bank, where the breadth of the head of the embankment may be (practically speaking) unlimited, the quantities in the table would be also unlimited, with respect to the tip; and would merely depend, upon the number that could be filled in the cutting, which is the only case, in which the general opinion—viz. that the capacity of a cutting limits the progress of the work—holds true. As this is the most important peculiarity, developed in the formation of em- bankments, we would recommend the reader to give most minute attention to the investigation of the formulae by which it is proved. An estimate of the cost per yard, incurred in excavating, and leading soil to embankment, may be easily made, by calculating tables similar to the last, for each particular embankment; and ap- plying the local value of day labour, and the ex- pense of keeping horses, to the results. FOREGOING SECTIONS. 131 Also the exact length of lead, at which a loco- motive engine may be more profitably employed than horse power, can be determined in a similar manner.” As these estimates must entirely depend upon the value of wages in the neighbourhood of the works; and as the price of wages varies consider- ably in different districts, it would be impertinent to the nature of the treatise, to attempt entering upon them. Our object was merely to develope the theory and practice, upon which railway cut- tings and embankments ought to be conducted. SECTION IX. Containing an investigation of the system of re- moving soil by means of barron's, and human labour. Having, in the preceding pages of this work, concluded our investigation into the laws which govern the formation of cuttings and embank- ments upon railways, when the means of trans- port employed consist of wagons and horse power; it remains to give the results of our inquiry into * Eighteen-pence per mile is the average cost of working a locomotive engine; so that, by comparing this, with the cost of horse power, the distance at which it would be most advan- tageous to employ the former, can be easily determined. 132 INVESTIGATION of the subordinate system of removing earth, by means of wheel-barrows and human labour. Upon commencing a cutting, the first por- tion of excavation is removed to embankment by barrow work; and this system is continued until the lead exceeds one hundred yards, or what is generally denominated four barrow runs. When this distance is exceeded, horse power and earth wagons are resorted to, as being more economical, and more easily worked in the lower gullet of the cutting. After the cutting has been extended this distance, and becomes deeper, that which is called the second lift,” is commenced; and this, with all succeeding lifts, is always worked by barrows, upon stagest or platforms, erected for the purpose. Wide plate 1, fig. 1, at a, b, and d. In some in- stances, a third lift is commenced, when the cut- ting is deep; but in all such cases, the superior advantages and facility which the adoption of the inclined plane affords, will, we hope, in a short time, render such an arrangement obsolete. Also, in the trimming off of the slopes of em- bankments, the slipsi and irregularities are re- moved—the parts which are found deficient, being supplied from those which are too redundant—by means of barrow work; and gravel, which has been led to spoil in the first instance, is always * Wide Appendix, Note 19. f Wide Appendix, Note 18. f Wide Appendix, Note 20. THE BARROWING SYSTEM. 133 removed back upon the balance line of the rail- way, to supply ballast for the permanent way, in a similar manner. These effects, produced by barrow-work, although partial in comparison to the amount of work done on a railway, seem, nevertheless, worthy of investi- gation; as it is desirable that no department should be left untouched, which can affect the ultimate object of the inquiry. In all cases, when barrow-work is adopted, it is necessary that the following arrangements be ad- hered to ;-viz., three men must be placed at the point where the barrows are filled, and one at every twenty-five yards forwards, to the place where the barrows are emptied. The three men, stationed at the point where the barrows are filled, are employed in filling each barrow as it arrives, and wheeling it one run,” (twenty-five yards). The man who wheels it the first run, hands it over to a man stationed at the end of it, and receives a returned empty barrow, with which he goes back; and the loaded barrow, which he has exchanged for it, is wheeled one run farther by the man he gave it to; who—at the end of the run next to the one on which the barrows started originally—re- ceives also an empty one, and returns to his former post; and so on in succession.f * Wide Appendix, Note 22. t If the reader refers to the third plate, and reads the description of it given in the Appendix, he will be better able 134 INVESTIGATION OF The length of the second lift—or the distance between the points where the barrows are filled, and where they are emptied into the wagons in the lower gullet—scarcely, if ever, exceeds two runs. It is generally equal to the length of one run. From this arrangement, it is evident, that there must be as many runners, minus one, (ex- clusive of the three stationed at each of the filling points,) and as many barrows, plus one, as there are barrow-runs emanating consecutively from the same point; and, that to prevent unnecessary delay, the time spent in filling an empty barrow, must be the same, as that required for wheeling a loaded one the length of one run ; and that required for returning with an empty barrow the same distance; both taken together. This accounts for three men being placed at the point where each barrow is filled; as two ordinary men, are able to fill an empty barrow, of the di- mensions now used; while one man is wheeling a loaded one forwards, and an empty one back- wards, a distance of twenty-five yards, upon a level. Although the aggregate distance, over which the barrows are wheeled,—or the distance between the points, where they are filled and emptied,—be any distance whatever, these circumstances will remain the same ; for whether there are more, or to comprehend what we have endeavoured to explain in the text, with respect to the order and progression of the barrows. THE BARROWING SYSTEM. 135 less, barrows in motion, at the same time, the returns to the point where they are to be filled, will be made in equal times; though not of the same individual barrows. Moreover, it is evident, that the quantity of earth removed in this manner, in a given time, (which is a circumstance peculiar to barrowing), depends, neither upon the number of men—the number of barrows—or the number of runs; but, solely, upon the number of stages erected; or, in other words, upon the number of different points at which the barrows can be filled, and the number of separate roads* which can be supplied from each. In general, three roads may terminate, and be supplied, from the same point. In barrowing up the slopes of a cutting to spoil, or down the slopes of an embankment, in order to fill up deficiencies at the sides; or, in fact, in any case, where the number of runs ex- ceeds one; it is always necessary, to have a square platform, 6ft. × 6ft., at the termination of each run ; upon which the barrows going, and returning, are exchanged, and pass each other. Having given these preliminary illustrations of the system, we shall now proceed, to state the most satisfactory experiments that have been undertaken in this department, and the deduc- tions arrived at from them. The following experiments, were made upon * Wide Appendix, Note 21. 136 INVESTIGATION OF the Great Western Railway, in the month of July 1838; in order to obtain constants, for the times spent in filling and wheeling a single barrow, one run; and from these, to calculate the average quantity of earth that could be removed per day—according to the barrowing system; and finally, the expense per cubic yard. ExPERIMENT 1. One barrow was filled, wheeled four runs, emptied, and brought back again, to the point where it was filled at first; in five minutes, and thirty-five seconds. ExPERIMENT 2. A single barrow was filled in fifty-eight seconds, —wheeled four runs forwards in two minutes and thirty-two seconds,-emptied, and brought back again to the place where it was filled, in two minutes and a half; making a total for filling, removing, emptying, and bringing back, of six minutes. ExPERIMENT 3. One barrow was filled,—wheeled four runs,— emptied, and brought back again, in five minutes and forty seconds. ExPERIMENT 4. Three barrows were filled,—wheeled four runs, emptied and brought back, in seven minutes and thirty seconds; but before the third returned, the barrow that first left the place where they were THE BARROWING SYSTEM. 137 filled, was loaded a second time, and wheeled the distance of two runs. ExPERIMENT 5. Three barrows were filled,—wheeled,—emptied, and brought back over four runs, in seven minutes and ten seconds, following consecutively; but, as mentioned in the preceding experiment, the first barrow was filled a second time, and wheeled the two first runs, before the return of the third. From these experiments, the two following tables result. Table, constructed from the results of the three first experiments; and showing the mean time which elapsed, while a single barrow was being filled, removed, emptied, and brought back, over four runs. TABLE, SHOWING THE RESULTS OF THE THREE FIRST EXPERIMENTS. gº &D ... a. º. º & rº * 33.33. ſº t to d : .# #. ii # # | #. 8 : # £3 #####. §§§ s 3 & REMARKS. o "E # ‘83 3 & E B 5 #5 ºn Hjá 2, #. ‘s 3 'a, 2 sº 3.c.5 .83 ; ... R. Žá 3.53 Å; ă § 3 ãº: 3. # ##### ## #: tº is š. l I 4 100 5/.35” These are the results of obser- M // f 2 1 4 100 6.00 5.45 |vations made upon single barrows. 3 l 4 100 5'.40” 138 INVESTIGATION OF Here we find, that five minutes and forty-five seconds, was the mean time spent, in filling, re- moving, emptying, and returning, with a single barrow, a distance of one hundred yards. There were five barrows working consecutively, while these observations were being made. Table, constructed from the results of the two last experiments; and showing the time which elapsed, while three barrows were being filled, re- moved, emptied, and brought back, a distance of four runs. This time includes that for filling and wheeling the tryo first runs, the barrow which left the filling place first; together with the filling of the barrow which left it second. TABLE, GIVING THE RESULTS OF THE TWO LATTER EXPERIMENTS. go 'd •º wº ta 5:33: 3 tº gº? 3.3 +5 £: on tº 5:33.5 #### §º a så | # | # ####| ###, # §§ *::: *** #####| | ######| #### REMARKS. 2: 3 ‘5 5 .# | #####| | ######| ### ; * ; 3.3 ####| | #3; ##" | #3 ź ## #####| | ##### ### i F #3 #F# 3 # * | 4 3 4 100 |.. 7.30 - - 7.20% 5 3 4 100 77.10” - 3rom. this table we perceive, that the mean time elapsed, from the moment the men com- THE BARROWING SYSTEM. 139 menced to fill the first of the three barrows, until the third one returned empty, was seven minutes and twenty seconds. But it is to be observed, that before the third returned, the first barrow was filled a second time, and wheeled tryo runs. Also, that the barrow which left second, was filled a second time, before the return of the third. There- fore, according to the first table, as five minutes and forty-five seconds must have elapsed, while the first barrow of the three was being loaded, removed, emptied, and brought back, over four runs; and again, as, according to the second table, the first barrow was filled, and wheeled two runs a second time, before the third barrow was brought back empty, at the expiration of seven minutes and twenty seconds; we shall have, 7' 20"—5'45" = 1' 35", for the time which elapsed, while the barrow which first left, was being loaded and wheeled two runs a second time; and it will be, likewise, the time which elapsed, from when the men commenced to fill the first barron, until they commenced to fill the third; because the time spent in filling the third barrow, wheeling it four leads, and back, must have been the same, as the time spent, while similar opera- tions were being performed with the first. There- fore, if this portion is taken from the total time spent, from when the filling of the first barrow was commenced, until the return of the third one K 2 140 INVESTIGATION OF empty; the difference will be the time spent in filling the first and second barrows. This difference is 7.20"—5.45"= 1.35"; being the same as the time for filling a single bar- row, and wheeling it two runs, or backwards and for- wards one run, as deduced from the results of the first table. Now, as the times required to fill two barrows, and to fill and wheel, backwards and forwards upon one run, a single barrow, are each equal to 1.35"; it is clear, that if we subtract the equal times spent in both cases, (viz. while a barrow was being filled,) that the remaining portion of time will be equal—or, in fact, that the times re- quired to fill the remaining barrow in the one case, and to wheel a barrow backwards and forwards, on the same run, in the other case, are exactly the same in amount. Hence, it is evident, that the size of the barrow must regulate the length of the runs. For the arrangements above stated, and what we have ar- gued from them, show that the length of each run must be exactly such as will allow of a barrow being wheeled over it, backwards and forwards, in the same time as another empty barrow of similar dimensions can be filled by two Iſle]]. The size of the barrows at present in general use upon railways, seems for every purpose the most convenient; both with reference to the load THE BARROWING SYSTEM. 141 which a man can wheel, and the length of run which it requires; each of these barrows, when heaped, contains about one-tenth of a cubic yard of soil; and the above induction shows that each can be filled in 1' 35 // -ā-- 67”, nearly, and wheeled backwards and forwards in the same time, over a length of twenty-five yards. We will now proceed to detail a set of experi- ments, conducted in a different manner; in order to compare their results with those just given. The following experiments were made upon the Birmingham and Gloucester Railway, near the village of Bredon, where a large quantity of bal- lasting material was “led to deposit,” + during the formation of the Northway, and Bredon's Norton COntractS. ExPERIMENT 1. Twenty-four barrows were filled, wheeled for- wards two runs, and tipped, in thirty-eight minutes and forty-eight seconds; which is the same in effect, as if they were filled, wheeled forwards * Soil is said to be “led to deposit,” when it is wheeled out on either side of the railway, and intended for use at some future period; in contradistinction to the term “led to spoil.” Gravel is chiefly run out in this manner; both for the purpose of expediting the excavation, and that it may be near at hand, to be used as ballast for the permanent road. 142 INNESTIGATION OF and backmards, and tipped upon one run, during the same time. ExPERIMENT 2. Eighteen barrows were filled, wheeled forwards one run, and brought back empty again, in twen- ty-five minutes, and forty-two seconds. ExPERIMENT 3. Eleven barrows were filled, wheeled forward upon two runs, and emptied, in eighteen minutes; which is the same in effect, as if they were filled, wheeled forwards, emptied, and brought back, upon one run. From the results of these experiments we can determine constants, (as regards the time which elapses while each barrow is being filled, wheeled forwards, emptied, and wheeled backwards upon one run,) equally as simple, and as correct—if not more so—as those obtained from the experiments previously given. Now, referring to the first of the latter expe- riments, we find, that twenty-four barrows were, in effect, filled, wheeled forwards and backwards, and emptied, upon one run, in thirty-eight mi- nutes and forty-eight seconds. Therefore, 38.48" 24 - 137 THE BARROWING SYSTEM. 143 is the period of time which must have elapsed, on the average, while each of the twenty-four bar- rows were being filled, wheeled forwards and back- wards, and emptied; when the distance to which the soil was removed, was equal to the length of OIle TUII). In a similar manner, we find, from the data afforded by the second experiment, that 29.42, -Ts- was the period of time spent, in filling, wheeling forwards, emptying, and returning, with a single barrow, over the length of one run. Also, from the third experiment, it may be perceived, that the time which elapsed, while each of the eleven bar- rows was going through the processes of being filled, removed, emptied, and wheeled back again, Over One run, was 18' :- = 1 .. 36” : 11 5 = 1.39" very nearly. From these experiments, and their results, we have been enabled to form the follow- ing table:– 144 INVESTIGATION OF TABLE, SHOWING THE RESULTS OF THE SECOND SET OF EXPERIMENTS. Distance iº wheeled Time spent | No. of T. #.t No. of . over, back-| infilling barrows and wheel- Remasks. experiment. wards and and wheel- working ing one forwards, ing. barrow in yards. g 1 50 38/.48’’ 24 1'.37” 2 50 29'.42" 18 I’.39” 3 50 18'. 11 H'.36” Now, upon taking the mean of the times spent, in filling, emptying, and wheeling, one barrow backwards and forwards, the length of one run, as given in the last and previous tables; we shall have a correct estimate of the time required, for filling a single barrow, wheeling it one run, emptying it, and returning with it, or another empty barrow, to the filling place. Or, in fact, an average estimate of the time elapsed, from when the filling of a barrow commences, until another returns empty to occupy its place; what- ever the number of runs may be. For, as we have shown before, the number of runs will make no alteration in the periods of time at which the empty barrows return ; nor in the number of THE BARROWING SYSTEM. 145 loaded ones which can be emptied in a given time; provided the number of barrows working, exceed the number of runs by one; so that if there were five runs, between the filling and tipping points, the same number of barrowfulls could be removed in any given time, as if there was only one run to be wheeled over ; although the expen- diture would be much greater, in consequence of the greater number of materials, and quantity of labour required in wheeling. Hence, taking the mean of the results of both tables, we shall have 1.35" I’.37" 1'. 39" 1'. 36." 4) 5.47" I’.37” _* for the mean time which elapsed, while a single barrow can be filled,—wheeled one run, emp- tied, and brought back; or in fact, a constant answering to the interval of time, between the emptying of each consecutive barrowfull, off each separate road. Hence it is evident, that if we put t, for the time in seconds worked, t 97=w will be the number of wagons that can be tipped, off a single road, in any given time. This gives a 146 INVESTIGATION OF result, of very nearly thirty-seven barrow-loads per hour, for each separate road. * Therefore, in any instance, where the number of separate roads that can be laid, is accurately determined, we can easily calculate the progress in any given time, by the formula, t 97 R representing the number of separate roads working, and the other letters the same quantities as before. Here it may be observed, that the results in any case, as regards the quantity of earth that can be removed, by means of barrows, in a given time, must solely depend upon the number of separate barrow roads that can be laid in ; and, that the distance to which the soil is to be removed,—the number of men employed,—and the quantity of × R =a'; * From this we can find the number of cubic yards of material that a railway-labourer can remove in a day; for we have seen, that two getters can supply each road; therefore, #=18.5, is the number of barrowfuls answering to the work of a single man per hour: and supposing, on an average, eight hours per diem to be actually worked, we shall have 18.5 × 8 =148.0 barrowfuls, for the work performed by a single man in a day; and allowing ten of these barrows to make up a 14 º cubic yard, we have iſ a 14.80 cubic yards of material ex- cavated per * by an ordinary railway labourer. THE BARROWING SYSTEM. 147 materials required, produce no other effect upon barrow-work, than increasing, or lessening the ex- penditure. For although the quantity of materials and number of men required, to remove soil over a distance of one hundred yards, will nearly amount to double that which would be required for a dis- tance of fifty yards, and consequently increase the expense, nearly two-fold ; yet, the number of barrows that could be removed, in both instances, in a given time, would be exactly the same; pro- vided the number of roads worked were equal. As we have seen before, that the barrow, now in use upon railways, can be wheeled by one man backwards and forwards twenty-five yards, while two other men are excavating and filling a quan- tity of material equal to its load; the number of runs answering to any distance, between the filling and emptying points, will be # × R=r 3 L, being the length between the filling and empty- ing points, in yards,-R, the number of roads working-and r, the number of runs required. From this formula, the quantity of materials necessary for erecting the stages and roads, (such as trussels, planks, &c.) for any length, can be easily calculated. Again, in order to find the number of barrows that is required for working any number of roads— 148 INVESTIGATION OF be their length what it may—it is only necessary to consider, that the number of barrows required for each road, must exceed the number of runs in it by one ; in order to admit of one stationary barrow being filled, while the others are in motion, and emptying. Hence, the general expressions for the number of barrows, will be {#+1}x R= B. Or, r—HR-B ; where B, represents the number of barrows re- quired, and the others stand for the same quan- tities as before. Finally, the number of men required to execute any quantity of work, will be found by |## 2} . R=N; where the letters L, and R, represent the same quantities as before, and N the number of men required. The first of the formulae above given, show, that the number of separate roads working, solely affect the number of barrows that can be emptied in a given time; in a manner exactly similar to that, in which the number of shunt roads, that can be fixed upon the head of an embankment, deter- mines the number of wagons that can be tipped ; so that the progress in the former, as in the latter, depends in no wise upon the distance to which THE BARROWING SYSTEM. 149 the material (whatever it may be,) is to be re- moved, but upon the number of roads that can be laid down. On the other hand, the remaining formulae demonstrate, that the ultimate cost of removing material, according to this system, increases pro- portionally with the distance, over which it is to be wheeled; for they show, that the number of men, and the quantity of materials required, (viz., planks, barrows, trussels, &c.,) must be increased after the first run, in direct proportion to the length, between the points where the barrows are to be filled, and where they are to be emptied. Perhaps it may be useful to remark, that in working the second lift of most cuttings, no more than six barrow roads can be made available with advantage; viz: two at the face, and two at each side of the second lift. But when the system is adopted, in breaking “the first ground *" in a cutting, the number of barrowfuls that can be removed will vary, in all cases, with the magni- tude of the work. And also, that the quantity removed in a given time, will be always inva- riable in working the second lift; for the extent of it is, practically speaking, the same, in all cut- tings; and so with respect to the third lift; but * By breaking the first ground, contractors, and their work- men, mean the excavation of the first portion of a cutting, pre- vious to entering upon it with wagons and horses. 150 INVESTIGATION OF this, as we have mentioned before, is being gradu- ally superseded by the adoption of the inclined plane. These combined results prove, that after the distance between the points where the material is excavated, and where it is to be deposited, exceeds the length of four runs, (one hundred yards,) the adoption of the barrowing system becomes more expensive, as a means of transport, than that afforded by the use of wagons and horse power. In estimating the expense that would be in- curred, in the execution of any description of earthwork by means of barrows and human labour, we have only to apply the price of wages and materials, in the neighbourhood of the work, to the results given by the three last formulae, and to divide the quantity thus found, by that derived from the first; and the quotient will be the cost per barrowfull; or, as on an average, ten loads of the description of barrow commonly used upon railways, are contained in a cubic yard; after multiplying the above quotient by ten, we shall have the net cost per cubic yard. This will be found to increase much more rapidly than might be expected, with the distance between the points of excavation and deposit. In order to render this process more adapted for practical instances, by condensing the previous formulae, we shall give a general one, showing the THE BARRow ING SYSTEM. 151 amount for which any work executed upon the barrowing system, may be contracted for; as fol- lows. If we represent by r, the wages of one man per day, together with the per centage upon it, and the quantity of materials required for a single run, which the contractor may deem suffi- cient remuneration for his risk and services; we shall have L L L A =b, Or, hence, l, (3L-H3):r. T .257 t ' or otherwise, b_11.64 (Lr--r), t the cost per barrow in any case. Therefore, as ten barrows go to the cubic yard, on an average, (3L-H3). r = C: .0257 t T ~ * 152 INVESTIGATION OF or otherwise, C–11.04 (i. r-Er), 1 the cost per cubic yard, for which the contractor might undertake to execute the work, with rea- sonable profit. The results of these investigations into the sys- tem of barrowing—the reader will observe—show that no material improvement can be made in it; nor indeed was it to be expected, as the system is so simple and free from complication, or the influence of collateral circumstances. It may be well, how- ever, to remark, that they prove the length of each run to be dependant upon the size of the barrows used, and not constant, as is generally supposed. Upon attentively considering the results, con- tained in the two principal departments of this inquiry, viz: the removal of earth by wagons, and the removal of it by means of barrows;–it will be perceived, that both systems—provided the former is regulated in accordance with the formulae we have given,_are exactly the same in principle; or in fact, that the theory we have ad- vanced with respect to the management of a work, carried on by means of wagons and horses, has been already brought into practice in the system of barrowing. The arrangements in the latter, THE BARROWING SYSTEMI. 153 being the same as those shown to be most advan- tageous in the former; and both being evidently the same in principle, although upon different scales of magnitude. It will also be seen, that the principles upon which former authors attempted to develope the general laws of excavation and embankment, were evidently adopted, without any reference to the practical working of the system ; and, that the mode of making their observations, (whenever they were made), was much too isolated, for the pur- pose of affording an expanded and comprehensive view of the various agencies—collateral and direct —which are continually acting, one upon the other, and by which the ultimate results are col- lectively influenced. The error into which they have fallen, seems to have consisted in assuming, as their constants, quantities in the abstract; or in observing in detail, instead of the aggregate; and adopting the results of these separate obser- vations, as if entirely independent one of the other: and therefore it is not to be wondered at, that many matters, essential to the thorough sifting of the subject, were altogether excluded ; and that the arguments founded upon these self-begotten phenomena, led them to a belief, in the inverse ratio to probability, if not of possibility itself. Thus, the antecedents being widely unconnected, and, from their number, subject to frequent error; J. I54 THE BARROWING SYSTEM. the consequents derived from their combination, turned out utterly fallacious. The method we have pursued is exactly the reverse: our constants depend upon observations, made upon the com- bined effects, produced by the various agencies in the aggregate; and, by an analysis of these, we have descended, step by step, to the details; and not advanced, from the minutiae of detail to ab- stract generalities, which have no foundation in truth. A P P E N D H X. NoTE 1. Wagons:—There are various kinds of wagons used upon Railways, differing both in form and dimensions; but the best adapted for general purposes, is that delineated in plate 2, fig. 1, which contains, when heaped in a comical form, 3.12 cubic yards. The side-tipping wagon is also of great use; but the only difference in the construction of the two is, that the latter extends over the frame, more on one side, than the other, in order to facilitate the tipping. The former are always used in front of the tip, as at l, in fig. 1, plate 1; while the latter are emptied over the sides, to fill up any slips, or deficiencies that may occur; as represented in figures 5 and 6, plate 1. The principal object to be attained, in the construction of earth wagons, is a convenient height. Some are so high above the rails, that a much greater exertion is required in filling them, than if they. were lower; but on the other hand, there is a certain point, beyond which, the height camot be decreased, without encountering a greater evil, in the diffi- culty which will be experienced in tipping; especially, when I, 2 156 APPENDIX. the material with which they are loaded, is of a loamy and adhesive nature. The diameter of the wheels should in no case, be less than two feet six inches; and wheels three feet in diameter are decidedly to be preferred, if every circumstance is considered; both with respect to the most convenient height of the wagons, and the facility with which they can be drawn by the horses. Oftentimes, when the length of the lead renders it more economical to work a locomotive engine, much inconvenience—besides an enormous increase in the amount of wear and tear—arises from the diameters of the wheels being too small. NOTE 2. Tºpping wagons:—A term used by the workmen, synonymous with emptying wagons over an embankment. This is dome in two ways: one, by running each wagon at a smart pace— say six miles an hour—towards the head of the embankment, and detaching the horse when within about twenty yards of it; when the wagon is precipitated, by the velocity it has ac- quired, against a strong piece of wood, (generally beech or elm,) 5 feet 6 in. × 9 in. × 12 in., which is fixed on the end of the embankment. The concussion which the wagon re- ceives, capsizes the body with its load; as represented in plate 1, fig. 1, at l. The other method is by simply raising the body of the wagon off the hinder axle, as shown in plate 1, figs. 4, 5, and 6. This latter method is, however, nearly obsolete, except where side tipping is carried on. One of the most important desiderata in the arrangement of a work, is a good supply of active and intrepid men for attendanee upon the tip; as upon the efficiency with which that is managed, will, in a great measure, depend the economy and progress of the other departments. APPENDIX. 157 NOTE 3. Getters and Fillers:—The getters in a cutting, are the men who use the pickaxe, or loosen the material; so as to render it smaller, that the fillers may cast it into the empty wagons. One getter, is generally able to supply two fillers, and one wagon. NOTE 4. Tºp:-This term, as used by the workmen, is synonymous with the head of the embankment, or place where the wagons are emptied. NoTE 5. Lead:—The distance, between the head of an embank- ment, and the face of a cutting: which varies of course in every case, as the work advances. NOTE 6. Side tipping:—A term used, when the wagons are emptied over the sides of an embankment, in contradistinction to front tipping. See plate l; where front tipping, or tipping over the head of an embankment, is shown, at l, in fig l; and in fig 4: and side tipping in figs. 5 and 6. NOTE 7. Dressing off slopes:–When an embankment, or cutting, is first run out, the inclinations given to the sides, are generally left in a rough state; or at such a rate of inclimation, as the material will stand at; so that, upon forming the body of the work, it becomes necessary to fill in, and take off, at several points along the sides, to give them a uniform appearance. This operation is called trimming, or dressing off, slopes. 158 A PPE NIDIY. NOTE 8. Sets of wagons:—A set of wagons, denominates any num- ber of wagons which are filled, removed, and emptied together; and the number of sets, always depends upon the length of the lead, if the proper system of arrangement is adhered to; but it generally consists only of three. ^ NOTE 9. Battery head:—A term sometimes used, especially in the north, for “tip,” or “head,” of an embankment. NOTE 10. Temporary, or contractor's road:—These roads consist, generally, of fifteen feet iron bars, T shaped, and weighing on an average 35 lbs. per yard run; which are fixed upon cross sleepers, 9 in. x 5 in., with double chairs at the end of each rail, and a half chair at each intermediate sleeper. The form of the rails, and plan of this description of road, are given in plate 2; where fig. 5 represents the section of the rail, and fig. 4 the plan of the road when laid. The dimensions of the rail, generally used by railway contractors, seem too small; as a considerable portion of power is wasted in drawing over them, which might be saved, if rails weighing 40 lbs. to the yard, were used instead. However, on long embankments, when it becomes necessary to work a locomotive engine, it is absolutely necessary, that rails of much greater weight than those in general use, should be procured. NOTE 11. Stocking Earth.-A term used by the workmen, to denote a mode of excavation, similar to undermining. For instance, when the soil to be excavated is very stiff, the getters perfo- rate underneath, until the superincumbent weight falls by its APPENDIX. 159 own leverage; and then, if the material is very tenacious, they break it into small lumps, in order that the fillers may be enabled to cast it into the wagons, or barrows, with the shovel. The perforations, or channels, made in this method of excava- tion, are called stocking grips. NOTE 12. Bumpers:—The pieces of wood, which are placed on the head of the embankment, at the termination of each sperm road, against which the wagons are propelled, when they are to be tipped. The cross section of a bumper may be seen at m, Fig. 1, plate l; and a longitudinal section of it at g, Fig. 4. NOTE: 13. Side-Cutting:—A term used to represent excavation, be- yond the boundary line of the railway. This is often resorted to, when the quantity of material, included between the fences of a cutting, is insufficient to complete the adjacent embank- ment. The slopes, given to the sides of these cuttings, ought never to be less than six to one; in order that the sur- face may be resoiled, and rendered fit for agriculture or other purposes, after the quantity of material required, is removed. As a specimen of these cuttings, we cannot refer the reader to any better executed, than those upon the Birmingham and Gloucester Railway, between Cheltenham and the village of Eckington. In many of these, it is difficult to distinguish the original, from the made surface; and the ground has been rendered as eligible for agriculture, as it was before the sub- soil was removed. It is a question well worthy of every en- gimeer's attention, as to whether, in many instances, it would not be more economical to form the embankments chiefly out of side-cutting: and lead the material in the cuttings to the nearest spoil bank. The value of the property through which a railway passes, will, of course, determine this. 160 APPEND IX. NotE 14. Gullet:—This represents the furthermost part of the cut- ting, where the front wagons of each train are filled. It is sometimes called the lower chamber, when more than one lift is made. Its dimensions ought to be fifty feet long, twenty feet broad, and eight feet high; if the extent of the cutting will allow of them. The Gullet is that portion of the cutting shown in plate 1, fig. 2, where the wagons, o, o, o, &c., are situated. NOTE 15. Spoil Bank:-In contradistinction to side-cutting, this term refers to the deposit of material, taken from between the fences of a railway, when the quantity, or cubical contents in a cutting, exceed that of the adjacent embankment. These banks, if properly constructed, may be made as valuable for agricultural purposes as side cuttings; by resoiling, and trim- ming the slopes, at an inclimation of six to one. NOTE 16. Siding:—A siding is a road run out of the main road, and joined with it at both ends, as shown in plate 1, fig. 2, at w, w, &c. The length of a siding, will always bear a certain proportion to the number of wagons in each set; or, in other words, to the breadth of the head of an embankment. NoTE 17. Sperm, or Shunt Roads:–These are roads, branching out of the main road, at the face of the cutting, and at the head of the embankment; they are shown in plate 1, fig. 2, at P, P, &c. The number of these roads, will always depend upon the magnitude of the work; and with respect to the head of an embankment, the greater the number that can be fixed upon APPENDIX. 161 it, the better; for the more points there are, to tip from simul- taneously, the faster will be the progress, and the greater the number of wagons that can be worked in the adjacent cutting, from which it may be supplied. NOTE: 18. Stages:—A term synonymous with barrow runs—a stage being reckoned twenty-five yards long. Trussels:—A support for the planks which compose each road:—a large description of tripod, or stool; as may be seen in plate 3, at D, D, &c. NOTE 19. Second Lift:—The second lift, or chamber, in a cutting, is that in front of the first, and generally eight feet above it. This lift, is always worked with barrows; and is of the same length, but ten feet wider, on each side of the centre line of cutting, than the first lift. As the inclination given to the sides of the cutting, in some instances may not allow of this, it is sometimes narrower. The second lift is shown in plate 1, fig. 1, immediately above a, and in the second figure of the same plate is the plan of it, between the points n, n, &c. and where the wagons, o, o, &c. are situated. NOTE: 20. Slips:—A term used to denote the contraction, subsidence, or sliding away of the foot of a cutting or embankment; these accidents are of frequent occurrence, and the only effectual remedy for them is drainage. They are always removed by barrow-work, when they take place in the side of an embank- ment; but with wagons, when they occur in cuttings; and the excavation, which is thus taken out, is well puddled, and pun- med, in 18 in. layers; until that part of the slope, where the I 62 APPENDIX. slip occurred, is made up in uniformity with the rest of the cutting or embankment, as the case may be. Piling at the foot of the slopes, is often resorted to ; but we have never known it to answer the purpose fully: so that, when once the fissure appears at the back of a slope, it is, eventually, the best plan to remove the slip altogether, and pun it in again as stated above. NOTE 21. Barrow-road –This consists of planks, laid at each end on trussels or tripods, over which the barrows are wheeled; the planks must be 11 in, broad, and from 2in. to 2% in. deep ; the length of a road may vary, in executing earthwork upon railways or canals, within 150 yards; but, in the former in- stance, it ought not to exceed 100 yards, unless under peculiar circumstances; such as leading to spoil at a short distance, or supplying ballast, &c., for the permanent road. The barrow- road is represented in plate 3, at c, c, &c. NOTE 22. Barrow-run :-A term used to signify the length which each man can wheel a barrow, while one of similar dimensions can be filled. Several of these runs, may comprise a barrow- road ; but upon railways, when the small barrow is used, the length of each run ought to be 25 yards, as one of these bar- rows can be filled in the same time, that it can be wheeled that distance. DESCRIPTION OF THE PLATES. As there are several technical terms, unavoidably used in the text ; concerning which, none but men minutely conver- sant with the mode of excavation and embankment, adopted upon railways, can obtain any definite ideas, even with the aid of elaborate descriptions ; it was found necessary, towards a thorough comprehension of the work, to append a few plates, and offer such explanations upon them, as were likely to be of use to the reader. Description of Plate I. The first figure in this plate represents the sectional eleva- tion of the interior of a cutting, and the side view of an em- bankment, in the manner these works are generally carried on. The space immediately above a, is that portion of the cutting called the second lift. This lift is always worked with bar- rows, and is generally eight feet in height. The barrows, when filled, and wheeled over the second lift, enter upon the stages, b, (which are erected over the lower chamber, h,) and them emptied into the wagons as represented at d : the stages, upon which the barrows are wheeled, are supported by beams laid across the lower chamber, as shown in fig. 3. at a. The space over h, represents the lower lift, gullet, or cham- ber in a cutting ; into which a certain number of wagons, e, e, &c., (according to the extent of the cutting) are drawn, and there filled, partly by men stationed in it, and partly by the men working in the second lift, a, in the manner stated above: frepresents a getter in the act of /alling the material, by un- derstocking it and g, g, fillers, or the men who load the wagons. 164 APPENDIX. Immediately above i, may be seen an empty train, returning towards the gullet after being emptied over the tip ; in order to take the place of the wagons e, e, &c. and to be filled again. The wagons under the letter j, are those which having been filled in the lower gullet, and removed sufficiently near the tip, are then placed in a siding, and drawn out singly, at the rate of about five miles an hour, by a horse ; (as shown at k,) until it comes within twenty yards of the end of the embank- ment; when the horse is suddenly detached, and the wagon is precipitated against a piece of wood called the bumper, by the velocity which it has acquired; and is thus tilted over, off the hinder axle, as shown at l. Immediately above m, the bumper, or piece of wood against which each wagon strikes, is shown ; one of these is placed at the end of every shunt road. It may be observed, that the road (or surface of the embank- ment,) is a little inclined towards the tip, upon which the bumpers are placed. This is done in order to facilitate the progress of the wagons, after the horses are detached from them : for when the road is nearly level, it is necessary to put the horses to a much greater speed, in order to insure the safe tipping of the wagons ; and in this case, much difficulty is always experienced in detaching the horse: which often causes loss of life among the men appointed to the tipping department. Description of Fig. 2, Plate I. In the second figure, a plan of the cutting and embank- ment, represented by Fig. 1, is given. In this figure, n, n, &c., represent the points where each of the barrows, on the second lift, are filled. These points are commonly called stocking grips:—o, o, o, &c., represent the empty wagons just returned from the tip; p, p, &c., are the shunt roads in the cutting and on the embankment; but those on the embankment are sometimes in contradistinction called sperms, although in APPENDIX. 1.65 every respect similar to the ones in the cutting; g, is a wagon run in on one of the shunt roads, to receive the material which must be removed, in order to trim off the lower parts of the slopes to their proper inclination, as the bottom gullet advances—which is in every respect an arrangement most de- sirable, as it is a great preventative against slips;–r, represents a switch, which consists of two railway bars bound together to the proper guage, (4ft. 8%in.), and moveable at the ex- tremity nearest to the end of the main road, (as at s, s, &c.); so that the other extremity may be made to coincide with the direction of the shunt roads, as shown by the dotted lines at t, t, &c.; u, u, u, represent the main road, upon which the trains pass up and down from the cutting towards the tip ; v, v, re- present the sidings, which the results of our inquiry into the effects of the lead prove to be necessary, in order to allow the sets or trains of wagons to pass each other, when the number of wagons in each set is proportioned to the magni- tude of the tip-head; w, w, &c. are the filled wagons, which, after being removed from the cutting sufficiently near the tip, are placed in a siding close by, and thence drawn one by one, (as previously explaimed), for the purpose of being tipped ; w, represents a wagon in the act of being tipped by the force with which it comes against the bumper, after the horse has been detached from it. Description of Fig. 3, Plate I. This figure shews a section of the cutting through F, G, when a', aſ, are the sides of the second lift, and 6', the lower gullet. The indentations, c', c, are the grips formed with the pickaxe, and continued until the superincumbent mass, d", d", is completely undermined, and falls down. These grips are formed for the same purpose as the stocking grips ; and differ 166 APPENDIX. only inasmuch as the former are perpendicular channels, and the latter horizontal. Description of Fig. 4, Plate I. In this figure, the end view of the tip is represented, where e', shews a wagon in the position of being tipped;—f, one just tipped, with the horse attached to draw it back, in order to make room for another loaded wagon;—and g, the bumper, against which each wagon is precipitated. Description of Fig. 5, Plate I. This figure gives a side view of the embankment, when side tipping to dress off the slopes, is carried on. It will be ob- served, that these wagons are not tipped in the same manner as those used for front tipping, as it is necessary that each wagon should be lifted off its frame by the workmen, and not run against a bumper for that purpose, as in front tipping. Description of Fig. 6, Plate I. This figure represents the cross section of the embankment, at H, I, in the former figure, and shows the method in which the wagons are lifted off their frames. The method of side tipping, if it could be always adopted, would be much more advantageous than front tipping; for any number of wagons, according to the former arrangement, might be emptied simul- taneously; while, according to the latter, the number that can be emptied, must, in every case, depend upon the magnitude of the embankment—or, in other words, upon the number of shunt or sperm roads that can be fixed upon it. Plate II. Fig. 1. This figure represents an earth wagon, drawn to a scale of twenty feet to an inch. There are various sizes of earth wagons, APPENDIX. 167 but that given in the plate is the most convenient, and affords greater advantages for working than any we have met with; for it combines the advantages of carrying more material at each trip, and at the same time of allowing as many sperm --roads being placed on the head of an embankment, as any other size. Each of these wagons, when heaped in a comical form, will contain 3.12 cubic yards of loose material; which, in general, may be reckoned equal to 2% cubic-yards of earth in its solid state, or previous to its being excavated. Each of these wagons cost on an average 2622, and contain 24.50 cubic feet of timber. As follows, we have given the dimensions of the parts in detail, which may be found useful to the practical engineer or contractor: — Dimensions and weights of the timber, and iron-work, in the description of wagon represented in Plate 2. fig. 1. Tömöer Work. Pedestal Frame. ft. in. in. in. 1 Head-piece, elm 5 2 × 10; x 4 2 Elm pedestals, each 5 10 × 9 × 4% I Fir end-piece 3 5 × 5 × 5% Body. 2 Bumpers, each. 8 3}× 6 × 5 4 Shoots; three fir, and one elm . 6 4+ x 5 × 5 2 Chocks, elm 2 8 × 6 × 4 1 Head-board, elm . 6 3% x 1.3 × 1% 2 Side-boards, elm 6 8 × 1.3 × 1% 1 Tail-board, elm 6 9% × 1.3 × 1% 8 Bottom-boards in all, elm . 6 6 × 6.6 × 1% Iron Work. Cwt. qrs. lbs. 2 Cast-iron tipping blocks 0 2 4 Average of small iron-work . gº . 4 0 0 4 Pedestals º tº tº tº I () 20 2 Pair of wheels, with axles ſº g . 12 0 0 Total 17 2 24 168 APPENDIX. Plate II, Fig. 2. Represents the most convenient sized barrow, for exe- cuting earthwork upon railways. This figure is drawn to a scale of twenty feet to an inch. When filled well, these barrows contain 2.70 cubic feet of loose material. The wheels consist of cast iron, and the sides and bottom of elm board- ing, one inch thick. The handles are generally made of ash, well seasoned; and the net cost, when new, averages at seven- teen shillings apiece. Plate II, Fig. 3. This figure represents two cross sections of the same embankment: —c, b, h, g, the section as it would appear, when originally run out; and a, b, f, e, the section according to which it is to be finally formed. Here it will be seen, that the extra breadths of c, a, and 6, d, are of great advantage; as by running out an embankment in this manner, a greater number of sperm roads can be laid on the tip head, than if the embankment were, at first, formed to its pres- cribed width, as shewn on the engineer’s sections. The advan- tage to be derived from this, is more fully discussed in the fifth section, to which we refer the reader. The areas Ö, d, i, and a, e, j, (respectively equal to i, f, h, and j, c, g,) are cast to the bottom of the slope, on each side, and trimmed off to the regular inclination, to which it is intended the embank- ment is to be finally formed. Plate II, Fig. 4. The fourth figure in this plate, represents the plan of a contractors' road, as generally laid. At a, and a, are represented the junction of the rails; where what is termed a joint chair is made use of, as the best method of fastening them together, and keeping them in proper guage. At b, b, &c. APPENDIX. I69 are shown the half chairs, which are fixed on the outside of the rails, at every intermediate sleeper, between the joint chairs; in order to keep the rails from being pushed outwards, by the flanches of the wagon wheels. This is sometimes done by spiking down the rails on the sleepers; but the use of half chairs is much more to be preferred. At the joint chairs, the rails are firmly keyed in the chairs, with iron spikes, as shown in figure 5, at e :-A, A, A, &c., represent the sleepers, which consist generally of larch, beech, or other durable tim- ter. The sleepers are generally laid at distances of two feet six inches apart; and the rail beds full upon them; but some- times, they are as much as three feet and more apart: the dis- tance depending upon the strength of the rail, in all instances. These roads always rest upon a substratum of gravel, mine inches, or a foot thick, and the gravel is well rammed under, to support the sleepers. Plate II, Fig. 5. In this figure is represented the cross section of the rail, generally used upon contractors’ roads. The figure is drawn to one twelfth of the full size, and shows the method in which the rail is keyed in the chair, by the small iron spike or plug, at c. These rails weigh thirty-five pounds to the yard, and are each fifteen feet long. They cost about zéll per ton, when bought new. These rails are evidently unfit for the working of a Locomotive engine; but will answer well enough, when the work is carried on by means of horses only; for we have known loads of five tons to pass over them —when the sleepers were well packed, and two feet six inches apart—without causing a permanent bend. M 170 APPENDIX. Description of Plate 3. This sketch represents the appearance of the cut- ting at Bredon, during March 1840, when the slopes were being trimmed off, and the ballasting of the cutting, for the permanent way, commenced:—the ballast being procured from side-cutting. * In this sketch, A, A, &c., represent the side-cutting from which the ballast was procured, for laying the permanent way upon. At B, are represented the wagons, run in on a shunt off the main road, into which the gravel is filled out of the bar- rows. In the near ground, it will be observed that the face of the side-cutting has receded from the railway considerably; so that a considerable number of roads was necessary to be erected, in order to wheel the material from the face, on to the siding where the wagons are standing. These roads con- sist of planks, C, C, &c., laid upon upright trussels, D, D, &c. The figures round about, represent the men in the acts of getting, filling, and wheeling the material—each of which, it may be seen, is a separate occupation. A little beyond, in the distance, at A', may be seem another party of men, also emptying their barrows into the same train. Here, the face of the side-cutting being near to the shunt road, upon which the wagons, B, are standing, a different ar- rangement of the roads is adopted; for the distance over which the barrows have to be wheeled, before they can be emptied over into the wagons, not exceeding the length of one run, it is only necessary to lay in a number of single roads at small distances, and parallel to each other; the same barrow * For this graphic sketch we are indebted to our worthy friend, George Jackson, Esq., Architect to the Birmingham and Gloucester Railway Company. APPEND IX. 171 and its wheeler using the same road constantly. Now, the arrangement in the foreground, is quite different; for the length of the road being equal—say to four runs—it is neces- __sary that a double way should be made, for the empty and loaded barrows to pass each other; also, that there should be a small platform at the end of each run, in order to allow of each loaded, and empty wagon, being exchanged from man to man; because, as we have previously mentioned, in the ninth section, the same man does not wheel any of the barrows the whole length of the road; but only for the length of one run, and there receives another empty barrow, with which he returns to have it filled. For instance, on the first run, a man is represented, at a, wheeling a loaded barrow, with which he proceeds as far as 6, where another man has just brought back an empty barrow; both, it will be perceived, are going in a di- rection towards each other; and where they meet must exchange the barrows, and return in the contrary direction—one towards the face of the cutting, with the empty barrow, to have it filled —and the other, with the loaded one, towards the railway, to have it emptied;—if the length of the road is equal only to two runs;—or, when it extends longer, to give it over, at the end of his run, to another. In this manner each barrow proceeds, and returns, throughout the time worked. When the wagons at B, are filled, as we have described, they are immediately drawn out of the shunt road, and at- tached to a locomotive on the main line, as may be seen at E; and conveyed to the place where the material is to be de- posited. Sometimes, the wagons are removed by horses; but in any case, where the ballasting of the permanent way is in operation, it is productive of considerable subsequent injury to the road, to allow horses to walk over the surface of the ballasting. In fact, horses should not be allowed to enter upon a railway, under any pretext, when the use of a locomo- tive engine can be procured; but this ought to be more espe- M 2 172 APPENDIX. cially guarded against, during the period, in which the perma- ment way is being laid. We have known much trouble and expence to arise, from inattention to this, upon the opening of one or two lines. But to return ; on the opposite side of the railway, at F, may be seen a party of men, engaged in dressing, or trimming off the slope; and at the foot of the slope, at G, may also be seen, a train of wagons placed there, in order to receive the ma- terial which is removed, in the operation of trimming.—This is always done with the pickaxe; and to ensure its thorough performance, it will be found necessary to procure labourers of considerable experience upon railways, as the work requires great nicety, and when imperfectly done, cannot fail to offend the eye, besides reflecting great discredit upon the person who superintends the setting out of the work. Having now given such explanations, of the details of earthwork in general, as are likely to afford the reader of the foregoing inquiry, all the practical information about it which it seems possible to communicate upon paper—considering the number, and magnitude of the natural causes by which it is affected;—we will conclude, by recommending the general reader, to make himself personally acquainted, if possible, with the general appearance and features of any cutting or embank- ment, which may be in process of execution in his neighbour- hood, previous to his attempting to master the subject, as it will much facilitate his entering into the spirit of it. In fact, we doubt how—without the aid of a model—persons who have not some slight knowledge of earthwork previously, can get a thorough insight into that particular portion of the subject, which refers to the method in which the material is removed from cutting to embankment ; or in other words, how they can ob- tain accurate notions of the manmer, and arrangement, accord- ing to which the trains pass backwards and forwards.—These remarks likewise apply to barrowing.—But perhaps, (as is not APPENDIX. 173 unfrequently the case,) the difficulties which the Author had to encounter, step by step, in exploring the principles of a department in engineering science, hitherto unattempted (in a systematic way), may have superinduced a belief, that the difficulties are of greater magnitude than the real circum- stances of the case will be found to warrant.—That the reader may find the latter supposition true, is the anxious wish of the Author. THE END. 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