(52 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



do not come up to tlie performances of tbe latter engines by six miles an 

 liour. 



We see likewise in tlie comparison of tliese performances a mucli greater 

 consumption of coke per ton per mile, by tlie engines on the Great Western 

 Railway, than by tlie engines on the London and Birmingham Kailway ; and 

 the construction of the engines being nearly the same, we consequently find a 

 proportionate quantity of water, or quantity <jf steam, consumed. It is 

 scarcely necessary to say, tliat the quantity of water used, or weight of steam 

 employed, in a given distance, is a correct test of the power e.spended in per- 

 forming a certain quantity of work on that stage ; we can, therefore, besides 

 knowing the relative dimensions of the engines, apply this as a test of the 

 power employed by the engines on the respective railways in the performance 

 of a similar quantity of work. Adopting the mode of estimating the relative 

 powers of the engines by a well-known rule, viz., that the power of evapora- 

 tion by tlie action of the radiant heat of the fire-box, is three times that of the 

 communicative heat of the tubes ; the following table will show the relative 

 powers of the several engines on which experiments have been made, according 

 to this mode of calculation, to which I have added the actual powers exhibited 

 by the experiments, as deteiTOined by the quantity of water evaporated into 

 steam. 



T.iBI.E V. 



THE K1:I.\T1VK POWFRS OF Till; LNC.INKS ON TIIK Onr.^T WFSTEfiN, AND 

 I.O-NDON A.\D UIRMINGHAM R.ilLWAVS. 



We see by the above table, the comparative amount of power required to 

 pcrfov:r. the same quantity of work on the Great Western, and on the London 

 and Birmingham Railwiiy? ; arising partly from the much greater power and 

 \vei''ht of the engines, compared with the useful load on the former than on 

 the latter railway, and partly, as will hereafter be seen, on the increased resis- 

 tance oU'ercd by the rails and carriages. 



On examining the account of the e.vperimenis on the London and Birming- 

 ham Ilailway, it will be seen that, although the mean rate of speed is 32 miles 

 an hour, occasionally on some parts of the line the velocity was much greater, 

 the maximum being 40.9 miles an hour. I shall, for the present, defer mak- 

 ing any further comparison of these results, and shall now offer to your notice 

 some experiments made on other railways, as corroborative of the above. 



Through the kindness of my friend iMr. Booth, secretary to the Liverpool 

 and Manchester Railway, 1 have been enabled to make some experiments on 

 deflexion on that railway ; and the resident engineer, Mr. Edward Woods, has 

 furnished me with some experiments on the powers of the engines on that 

 railroad. 



T.\BI.E VI. 



SrMMAKV OF rXl'I-nlMFNTS ON THE I.IVKRI'OOr. AND M ANCIIF.STllR RAILWAY. 



railway, .and received from that gentleman a letter, stating that Iw had laid 

 my application before the Board of Directors, and that they had authorized 

 him to say that they had much pleasure in meeting my wishes, leaving the 

 arrangement in the hands of their engineer, Mr. Locke. 



On applying to Mr. Locke, he at once placed in my hands the result and 

 particulars of a most valuable set of experiments, made on the Grand Junction 

 Railway, and met me on the spot to arrange about any other experiments 

 which I might think advisable to make. 



Tlie following are the experiments made on the Grand Junction Railway 

 on the consumption of coke of the locomotive engines. 



These experiments are presented for a difi'erent purpose than the preceding 

 ones, the former gives the consumption of coke and powers of the engines, 

 with respect to speed, from the time of starting iit one end of a stage until 

 they arrived at the end of th.at stage, or the consumption and r.atcof travelling 

 during the time of performing the journey alone. The experiment,; on the 

 Grand Junction line gives the consumption of coke, from the time of lighting 

 the fire until the engine has finished the journey, including all the waste at 

 each end; or, in fact, .-.howing what is etpiivalent to the consumption in the 

 regular working ot the railway, from the time the fire is lighted until the 

 engine li.as iini.shed the day's work. 



Table VII. is the result of these experiments: — 



TABLE VII. 

 SUMMARY OP EXPF.HIMENTS ON THE GR \ND JI'NCTION RAILWAY ENfilNES. 



Havin" been informed, that several experiments had been made on the 

 Grand .lunctioa Railway, on the consumption of coke, and some portions of 

 that Line being piirticularly favourable with respect to gradients, for experi- 

 ments on the friction of the carriages ; 1 made application to Mr. .Moss, the 

 Chairman of the Directors, for permission to make some experiments on that 



The experiments were made for the purpose of ascertaining the comparative 

 qualities of the different descriptions of coke, and were consequently made 

 with the greatest care by Mr. Alcaid, the resident engineer. 



For the purpose of comparing this result, with that of the consumption of 

 coke of the engines on the Greiit Western Railway, I have m.ade out Fable 

 VIII., from documents furnished me by Mr. Saunders. „ ^ „ , 



We «ee therefore that these statements corroborate the result of the for- 

 mer experiments m'ade in a diiierent manner, and show, for the reasons pre- 

 viously explained, a greater expenditure of power, or consumption of coke, 

 on theCreat Western Railway, than on the Grand Junction Railway, for 

 theperformanceof the s,ame quantity of work. • . ., 



Ok a careful consideration of the d.ata furnished by these experiments, the 

 conclusions which appear to result from them, as regardsthe first proposition, 

 vi/.., the attainment of speed, &e., &c appear to be as fo lows :- 



1st That the extreme rate of speed, accomplished on the Great Western 

 Railway, 'has been 45 miles an hour, with the North Star engine, and with 

 a load of fifty tons, for a short distance, 



