THE CIVIL ENGINEER AND AUCHITECT'S .TOURNAL. 



47 



GREAT WESTERN RAILWAY. 

 [Wc trust that the importance of the following reports will be a 

 sufficient justification for having occupied so nikny pages of the 

 Journal. We hail intended to have made some remarks thereon, but 

 in consequence of our correspondent, " An Old Engineer," having so 

 ably commented upon them, we have refrained, for the present, 

 saying any thing further on the subject.] 



EXTRACTS FROM MR. WOOD'S FIRST REPORT. 



The increase of gauge has been from 4 feet 8j inches to 7 feet, and the 

 prominent reasons assigned for such a departure from the common width, is the 

 attainment of a higher rate of speed — increased literal steadiness to the 

 carriages and engines — a diminution of the friction by the use of wheels of a 

 larger diameter — and a greater space afforded for the works of tlie locomotive 

 engines. 



The deviation from the ordinary mode of constructing the railway, has been 

 the substitution ofcontinuouslongitudinal timbers, with piling at certiiiu intervals, 

 and cross transomes ; with iron rails of a particular form screwed down upon 

 the longitudinal timbers. 



The additional width of gauge has increased the breadth of the entire track 

 of the railway between tlie outside of the rails of the two lines (including the 

 breadth of the rails) from 16 feet .3 inches to 20 feet 10 inches ; consequently 

 all the works connected with the formation of the road will be increased to a 

 certain extent, but not in proportion to the above figures. The plan of continuous 

 wooden timbers and piling also involves an additional cost beyond that of forming 

 railways according to tlie ordinary method. 



The questions submitted to mo for consideration, therefore, appear to me to 

 he shortly these ; are the advantages professed to be obtained by this departure 

 from the ordinary plan of construction of railways and increased width of gauge, 

 realized? to what extent — at what additional cost — and are the advantages an 

 equivalent for the increased cost of forming the railway according to this plan, 

 viewing the whole subject in connection with the present state of the works ? 



Acting upon the principles hereinbefore explained as to the mode of 

 conducting tlie inqinry, it was my object, as much as possible, to subject all, or 

 as many as could bo, of the properties of this railway as contrasted with others, 

 to direct experiment ; certain advantages are stated to be dcri\'ed from tliis 

 departure from the ordinary width and plan of constructing railways, and the 

 circumstance of 23 miles of this railway having been opened, and having been 

 in operation since the 4th June, appeared to me to allbrd an opportunity of 

 subjecting to the test of experience, and of obtaining correct and indisputable 

 results by carefully conducted experiments, Hint which rested on coiijei lure, or 

 castliil oli^t'milion. 



It is perfectly true that a daily opportunity has for some time existed of 

 observing the rate of travelling with the passenger trains on your railway, by 

 which some result of the rate of speed accomplished, or likely to be realized 

 when a greater length of line was opened might be obtained, but the engines on 

 the Great Western differ in many respects from those employed on other rail- 

 ways, and also from each other ; it', therefore, extended observations had been 

 made on the rate of travelling, it was necessary to distinguish what was due to 

 the road, and what to the engines, and if any increased speed or greater per- 

 formance was accomplished, whether such was applicable to the railway itself, 

 or to the particular construction of engine only, and whether, by the application 

 of similar engines to other railways (if practicable), the same results would not 

 accrue. 



If this had been done, no doubt important and valuable information would 

 have been obtained, but that would have been, in fact, the very sort of inquiry 

 by your own people, which you have determined to entrust to others ; and it 

 may be remarked, that if the inquiry had been conducted by yourselves, it could 

 not have been at all conclusive or satisfactory in the comparison with other 

 railways, and without such comparisons it would have been useless. 



At the first outset of the inquiry, it therefore appeared to me necessary to 

 institute a set of experiments, to ascertain the actual performances of the loco- 

 motive engines upon your own railway ; with this information carefully obtained 

 we then had the real working powers of the railway ; by employing heavy 

 loads, we obtained correct data for determining the maximum wciglit which 

 the engines, then upon the railway, could drag, at determinate rates of speed ; 

 and by subjecting the engines to very light weights, we likewise determined 

 the maximum rate of speed with certain known loads ; and by recording the 

 quantity of coke consumed and water evaporated in each trip, we also ascer- 

 tained, with considerable accuracy, the comparative cost of motive power in 

 dragging different loads at different velocities. 



These experiments appeared to mo to be highly necessary and valuable, 

 inasmuch as whatever diil'erence of opinion might exist (in the absence of 

 correct experiments to ascertain the fact) as to the friction of the carriages, or 

 resistance of the road as compared with others, these experiments, by deter- 

 mining the real practicable expense of working the railway, would at once 

 ascertain what increased rate of speed could be accomplished, and at what 

 additional cost of motive power such higher rates of speed was attained. These 

 experiments would, in fact, anticipate, so far as the pnvcrs of the engines 

 reached, the experience of some years of regular work upon the railway, and 

 with more correct results. On my arrival upon the 1-ne on the 1 7th inst:int, I 

 therefore commenced a scries of experiments on the working powers of tlic 

 engines, which were crmtinued under my own observation during the ten days 

 I remained there, and are now in opi-ration, and will shortly be completed by 

 persons in whom 1 have perfect confidence. 



It would be premature, to say the least, at this stage of tlie inquiry, to give 

 any results derived from experiments not yet complete; but it may be some 



No. 17 February , 1831). Vol. H. 



gratification to the proprietors of this great work to state, that one of the 

 engines, the North Star, accomplished an average performance from London to 

 Maidenhead and back, of dragging 180 tons, including engine and tender, at 

 the rate of nearly .'iO miles an hour, and that on some occasions, for short 

 distances, a rate of 4.J miles an hour was attained. 



When the powers of the locomotive engines and capabilities of the Great 

 Western Railway are thus obtained, in order to comply with your instructions, 

 and contrast this information with the capabilities of other railways, it will be 

 necessary, in order to arrive at correct and conclusive residts, that we should 

 have the result of a similar set of experiments made upon railways of the 

 ordinary construction. Although isolated experiments have been made by 

 different individuals on several railways, and although I have made several 

 myself, it does not appear to me that a set of experiments have yet been made 

 sufficiently extensive and varied to fully develope the capabilities and powers of 

 other railways, so as to form indisputable data for contrasting with the experi- 

 ments made' upon the Great Western. The directors of the London and 

 Birmingham Railway, in the most liberal manner, granted me full permission 

 to make anv experiments on their railway, consistently with the noiiinterruptiou 

 of their traffic ; and Mr. Robert Stephenson, the engineer in chief, kindly 

 assisted mo all in his power, and furnished me with some experiments he had 

 made on that railway, on a former occasion. I deem it, however, my duty to 

 state to you that I do not think the information I am in possession of is sutn- 

 ciently extensive or conclusive as regards other railways to enable me to make 

 a comparison with the performances of the engines on the Great Western, so as 

 to arrive at an incontestible conclusion, nor do I think it right that I should go 

 into a comparative statement at all, unless the data be equally conclusive or 

 carefully deduced on both sides. The information 1 at present possess does nor 

 enable me to go further than report to you the performances of your engines 

 on the Great Western Railway ; and if it be your wish that 1 should comply 

 fully witl.i your request, and contrast their powers with the performances oil 

 other railways, it will be necessary that some experiments, similar to those 

 performed on your railway, should be instituted on some of the ordinary rail- 

 ways of a different width of gauge. It will not be necessary that the experiments 

 on those railways should bo equally numerous, as the engines on tlie other 

 railways are generally of one description, and consequently one or two seta 

 carefully conducted will be suflicicnt. It may be asked what practical advan- 

 tage will result from all these experiments to the interest of the proprietors of 

 the Great Western Railway ? The answer is shortly this : it is admitted thai, 

 the construction of that railway involves .an increased capital ; it is, therefore, 

 cpiite necessary to determine what arc the .additional advantages, in a practical 

 point of view, resulting from this mode of construction, and whether the 

 advantages are greater or less than are equivalent to the increased cost of 

 construction. 



These observations apply more particularly to the plan of construction of the 

 Great Western Railway generally, and to the capabilities of the entire system, 

 or to the increased gauge, and the mode of construction combined ; but it is not: 

 necessary to the adoption of an increased gauge, that the railway should be 

 constructed on the plan adopted by Mr. Brunei ; it may be con- 

 structed on some modified plun of that system, or it might even be 

 constructed on the pl.in of the London and I3irmingham, or Grand Junction 

 railways. Neither is it absolutely necessary, if 'an increased gauge be deemed 

 advisable, that such increased gauge should be precisely seven feet ; all these 

 are separate and distinct questions, requiring different and distinct investigation, 

 and, therefore, the simple acquirement of correct information of the comparative 

 capabilities of the Great Western Railway in its present state, with the other 

 existing railways does not appear to me to comprise the whole question ; it 

 appears to me to admit of inquiry whether the width of gauge adopted by Mr. 

 Hrunel is or is not that which conduces most to accomplish all the objects for 

 which a departure from the more established width was deemed advisable, and 

 also whether the mode of construction of the railway is the best that can be 

 devised, or in what way it can be improved, consistently with the objects 

 required to be attained, and with due regard to economy. 



The plan adopted by Mr. Brunei, as previously stated, consists of longitu- 

 dinal limber bearings secured by piles at proper distances, with cross transomes, 

 double at the joinings of the longitudinal timbers, and single at the intermediate 

 piles ; and upon these continuous bearings iron rails of a particular form are 

 fastened by screw bolts. 



It has been .illoged that one of the objects of the increased gauge was a 

 greater stability to the carriages, and consequently less vibratory, or greater 

 smoothness of motion to the passengers ; it appears to be, therelbre, one of 

 the subjects of inquiry how far this is realized,— whether such a desideratum 

 is accomplished, — and to what extent. Keeping in view the principle set out 

 with in this inquiry, of, if possible, subjecting to experiment mechanically every 

 minutia, rather than to rely on opinion, or the more fallacious evidence of our 

 senses, I had constructed an instrument for measuring and recording upon 

 paper all the oscillations or vibrations of the carriages, from one end of the line 

 to the other; and by transferring this instrument to the carriages of the ordi- 

 nary railways, incontrovertible evidence is obtained, and such as can be nppre 

 elated by any one, of the relative vibratory motion of the carriages on the 

 Great Western Railway, compared with the motion on other railways. 



We have thus produced a di,igram upj^n paper showing the number and 

 extent of the vibrations of the carriages, and hence it can not only be asccr- 

 tiiincd if there does exist less motion on this railway than on others of a less 

 width of gauge, hut to what extent: and thi3 is thus made cap.ible of being a 

 subject of aritiimetie.il detoimination. 



It was soon found, however, and this shews the importance of this mode of 

 investigation, that the motion of the carriages on railways was a compound one ; 

 that besides a vertical motion, it was composed of an horizontal oscillatory 



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