1844.] 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



211 



This amount exceeds Mr. Samuda's estimate very consiiierably, but the cause has been 

 suflBciently explained: I will merely now add that this branch of the inquiry has been en- 

 tered upon and pursued with the most anxious desire to under rather than over estimate 

 the cost, and that I am convinced the amounts now put down are below those which would 

 be found in practice. This is undoubtedly the fact, for it will be seen I have taken the 

 size of vacuum lube which was proposed by IVIr. Samuda, who I think does not appear 

 sufficiently to have appreciated the importance of fully providing for the large amount of 

 traffic which oftentimes flows simultaneously into a trunk line; which will be understood 

 by those who are well acquainted with the tratBc of the London and Birmingham Railway, 

 where it is not unfrequently the case, that on the arrival of the Irish Mail Packet, the 

 train is augmented to twenty and sometimes thirty carriat,'es, equal in weight to !)0 or 130 

 tons, which could not with due regard to the convenience of the public be divided, and 

 started at such intervals, as would of necessity be the consequence of working with this 

 size of tube. It must also be borne in mind that the present traffic consists of a mixture 

 of quick passenger trains with slow goods trains; and upon the atmospheric system, the 

 latter, which are very heivy, sometimes amounting to 250 tons, must be divided into seve- 

 ral trains, not only to bring them within the capacity of the tube, but also to prevent their 

 interference with tiie lighter passenger trains : this it will be necessary to consider when 

 the cost of working is discussed. 



The power of the engines, that I have assumed, may at first appear large, but taking 

 the engine on the Kingstown and Dalkey Railway as our guide, it will be found that the 

 power reckoned upon do-es not exceed that which would be required lo ensure sutEciently 

 high velocities, wiih oidy the acerage passenger trains which now travel on the London 

 and Birmingham Railway; and we must bear in mind, that, the atmospheric system 

 involves the necessity of employing very nearly the same power with light as with heavy 

 trains. The maximum power must therefore be regarded as continually in operation : 

 this is not strictly true, but the diflference of power of working the air pump at low and 

 high vacuums within the ordinary practical range, is confined to such narrow limits as to 

 render this statement substantially correct. The engine at Kingstown may be taken at 

 nearly 2nu horses' power and capable of moving a trainofaboutSti tons upon a gradient of Ui 

 feet per mile at 35 miles per hour. If we extend the length of tube to 3^ miles, when the 

 increased leakage is added, the power required to move even such a load, which is below 

 the average load of the London and Birmingham traffic, at this velocity, will exceed the 

 250 horses power, which I have assumed as requisite, and which makes the gross expense 

 .^11,000 per mile. 



By referring to the half-yearly statements of accounts of the London and Birmingham 

 Railway Company, it will be seen that the capital invested in locomotive engines up to 

 31st December, 1843, was ^171,974. 17s. 6d. For the purpose of arriving at the whole 

 capital actually invested under the head of power, we must add locomotive engine sta- 

 tions for repairing, 8ic. : this item is not separately stated in the accounts, but we shall 

 be safe tn taking it ^150,000, making the total investment for power ^321,974. 



It must be understood that I am not attempting here to comprise all the sums which 

 might come under this heading, supposing the accounts to be fully dissected : my only 

 object is to make a comparative estimate, which is done correctly enough without intro- 

 ducing such items as would be common to both systems. The comparison of capital 

 expenditure for power upon this basis, on the London and Birmingham Railway, would 

 stand thus : — 



Locomotive engines and stations 



Atmospheric apparatus for 111 miles, at ^11,000 per mile 



^'321,974 

 1,221,000 



Making a difference in favour of the locomotive system, as far as capital in power is con- 

 cerned, of ^a99,026. This large disparity in the cost of the two descriptions of power, 

 might, it is urged, be more than saved by a reduction in the original cost of construction 

 of the railway. This is partially true in the case of the London and Birmingham Rail- 

 way, but not by any means to the extent generally imagined. 



I cannot now attempt to enter into the miuuLije of this part of the subject, because 

 it would involve a complete revision of all the original plans, and numerous considera- 

 tions which could not now be fairly weighed. For the purpose, however, of carrying out 

 the comparison regarding capital in this particular case, we may suppose that a saving of 

 ^9UO,0UO might have been accomphshed in the original design, by the application of the 

 atmospheric system; still it would only have been a transfer of expenditure from exca- 

 vations, tunnels, and bridges, to steam engines and pipes. The ultimate capital would 

 thus have been the same. 



If we now take some other lines of railway with the view of ascertaining how far their 

 cost could have been diminished by the application of the atmospheric system, we shall 

 find, that, as the surface of the country becomes more favourable, the economy in con- 

 struction entirely disappears; and when we arrive at a perfectly plain country, such as 

 exists in the eastern counties of England, where few provisions are required in the form 

 of excavations, tunnels, and bridges, the application of the atmospheric system would 

 certainly double the origmal cost where a double line of rails is employed. The Grand 

 Junction Railway is a case where no reduction of original outlay could have been effected, 

 since ttie gradients already conform to the natural surface of the country throughout a 

 very large proportion of the whole line. The adoption of the atmospheric system in this 

 case would therefore have caused a very large augmentation in the capital of the com- 

 pany ; probably as much as ^SOOO per mile, being the difference of cost between the two 

 descriptions of power. 



I will now proceed to the comparative cost of working the London and Birmingham 

 Railway upon the atmospheric and locomotive systems ; and in doing this I shall exclude 

 all such items of ex|)ense as are common to both. These calculations, as well as those 

 which hava been entered into for determining the relative original outlay in construction 

 must be looked upon as merely approximate statements, without any pretension to 

 absolute accuracy. In adopting this method, it must recollected that while the cost of 

 locomotive power is taken from the accounts of the company, the principal items, and 

 only those which maybe taken ascertain, in the cost of the atmospheric system, are 

 introduced into the comparative statement: in the latter, many minor expenses, in the 

 absence of experience, must unavoidably be omitted; thus giving some advantage in the 

 comparison to the atmospheric system. 



The expense of locomotive power upon the London and Birmingham Railway, for the 

 year 1843, was as follows: 



Wages of engine drivers and firemen 



Coke 



Oil, hose pipes, and fire tools, pumping engines, and water 



Labourers and cleaners, waste and oil ... 



Repairs of engines and tenders .... 



Coals and firewood, expenses of stationary engine at 

 Wolverton, repairs of buildings, gas and incidental 

 charges ........ 



Superintendent, clerks' and foremens' salaries, and 

 office charges 



£9,673 

 25,541 



4,099 



4,191 



12,521 



3,172 



4,634 



£63,834 



The expense of working the atmospheric system for one year, I estimate 

 approximately as follows : 



Wages of engine men, 64 at 6s. \ 



„ stokers 64 at 3s, J 



The same during the night 



Coal, 172 tons per day at 9^. . 



Oil, hemp, tallow, and repairs at 5 per cent, on cost of 



engines ........ 



Superintendence same as locomotive .... 



Annual cost . ..... 



£10,512 



10,512 

 28,332 



20,000 

 4,634 



£73,990- 



I have already stated that the above sum has no pretension to precise accuracy, but 

 since I have intentionally omitted numerous items of expense, which roust aristi, (the 

 exact amount of which no ona can venture to predict, or to introduce into such a calcula- 

 tion with much eontideiice,) I prefer making the comparison under that aspect wliich is 

 the roost favourable to the new invention under discussion ; because I conceive the ques- 

 tion between the atmospheric and locomotive systems does not by any means, after what 

 has been advanced, depend on the mere annual coat of working. I shall content myself 

 with the above statement, which in my opinion sufficiently establishes the fact, that the 

 cost of working the London and Birmingham Railway, or any other line with a similar 

 traffic, by the atmospheric system, would greatly exceed that by locomotive engines. 



The items of the above estimate need some further explanation ; I will, therefore, now 

 proceed to give the views that have led me to adopt the data upon which it is founded. 

 The item of engine men and stokers is of course based upon what I believe would be 

 required if the atmospheric apparatus were organised in the most perfect manner, that is, 

 with a double series of engines. The second item, which is simply a repetition of the 

 first, is considered to be necessary, because the London and Birmingham Railway, and 

 several others, are in point of fact at work day and night, in consequence of either mail 

 or goods' trains occupying all parts of the line, during some hours of the night. The 

 mail trains of necessity do this, but the goods it may be said should be transmitted by 

 day: this may appear practicable on a cuisory view, but a mo: e intimate acquaintance 

 with the character of the traffic will satisfy any one that the transportation of merchan- 

 dize between various parts of the kingdom absolutely calls for the use of most railways 

 during the night. We must, therefore, look forward in making all our arrangements 

 upon the arteries of communication throughout the country, to their being made available 

 at all hours of the night, and during all seasons. Whatever exceptions any peculiar 

 locahty may present to this position, they will uot be found to affect the broad question 

 which is now under consideration. 



The item of eoal, in the estimate of working expenses, is obtained by supposing each 

 section of H^ miles to be occupied by two stationary engines of 250 h. p. each, that 

 this power is exerted during six hours per day of 24 hours, and that the rate of con- 

 sumption of coal is 41b. per h. p. per hour, including all the w-aste which would arise 

 arise during the 18 hours when the engine is not working, but the 6re alight. This time 

 of the engine's working, six hours per day, is determined by taking the present number 

 of passenger trains, (12,) and doubling the number of goods' trains, which now amount 

 to three, averaging lti4 tons each, in order to reduce their weight to the capacity of the 

 tube at a moderate velocity, thus making in all 18 trains per day in each direction : and I 

 have estimated 2u minutes as the least time requisite at each section to exhaust the tube 

 at its maximum uniform velocity. This consumption. It must be understood, applies to 

 the actual horse power, and not to the nominal power, which should in the present state 

 of engine building be rejected altogether, as much vagueness has been introduced into 

 the subject by two different standards of horse power having been adopted. I have 

 throughout this Report adhered to 33,000 lb. as the standard horse power. 



The two remaining items require no explanation. 



Before leaving this estimate, it is desirable to make an observation upon the items 

 omitted, and the reasons for doing so. The wear and tear of the longitudinal valve, and 

 the degree of attention which it will constantly require, are points upon which we yet 

 have no information. At Kingstown, about two men per mile are appropriated to the 

 application of the composition, for tbe purpose of maintaining the tightness of the 

 valve. These items are problematical, but by excluding them from the calculations of 

 cost, the result is exempted from doubt and dispute. On the other hand, I have thrown 

 the maintenance of way entirely out of the comparison, which would undoubtedly be 

 against the locomotive system ; but this has been strangely overrated by the advocates of 

 the atmospheric system. They have taken for comparison the contract price of main- 

 taining the London and Birmingham Railway, namely, £3^0 per mile, and assumed, 

 without stating any reasois, that the cost of maintenance would be, when the atmos- 

 pheric system was applied, reduced to 175?. per mile. To show the fallacy of such an 

 assumption, it is only iieccssiry to state that on nifiny public railways, the whole mainte- 

 nance is l"-! by contract to responsible parties, under 160/. per mile. Such discrepancies 

 are easily explained by the different materials through which the railway is constructed, 

 the character and extent of the works, and other circnmstances in no degree connected 

 with the abstarct question of maintaining the rails, blocks, and sleepers in working con- 

 dition. As a proof of this, it may be stated, that less than one-half the aggregate 

 amount of expense, included under the general head of maintenance, is expended in pre- 

 serving the rails in proper order; hence it is that I have given no credit tor the saving 

 under this head, aud considered it more than covered in the items I have excluded from 

 the cost of working the atmospheric apparatus. 



Ha*/ing concluded my observations upon the question of power, original outlay, and 

 cost of working, the two latter having reference chiefly to the London and Birmingham 

 Railway, I will now offer one brief remark on the application of the atmospheric system 

 to lines where the traffi'' is of very moderate extent. The London and Birmingham 

 Railway having an unparalleled traffic, it is one of the best cases, in a general point of 

 view, to which the atmospheric system could be applied. 



■ Let us now conceive it applied to a case of an opposite character ; for example, the 

 Norwich and Yarmouth Railway, which has cost about 10,000^ per mile, including car- 

 rying stock and evsry appurtenance. This line passes over a country in which the appli- 

 cation of the atmospheric system could have effected no economy whatever in the forma- 

 tion of the line, which has nut exceeded a cost of SOOOl. per mile. The application of a 

 single line of the atmospheric apparatus, woidd, in this instance, have added at least 

 b*)i)Ol. per mile, which upon 20 miles, the length of the railway, would amount to 100,000/. 

 The mere interest of this sum, at 5 per cent., is 5000/. per annum, whereas the actual 

 working of this line, including maintenance of way, booking-offices, porterage, and all 

 other constant traffic charges, has been let for 7000'. per annum, being only 2000?. above 

 the bare interest of the extra capital which would be required to lay down the atmos- 

 pheric apparatus ; an amount which would be quite inadeqate to meet the wear and tear 

 of the machinery alone, leaving nothing to meet the current cost of working. Here, 

 therefore, we have a case where the country is favourable, the original capital small, and 

 the traffic moderate, where the cost of the atmospheric system would be so burthensome 

 as to render it totally inapplicable. 



The Report then proceeds to comment upon the comparative velocities, 



safety, and casualties, arising from defects in the machinery of both the 



- In this estimate It has been assumed that the atmospheric apparatus is laid down at 

 the time that the railway is constructed, and that a saving is effected iu the construction 

 equal to the additional cost of the apparatus : if however it were applied to a line already 

 construted, such as the London and Birmingham Railway, the interest on the additional 

 capital required at 5 per cenf. would in that case amount to 44,963/. per annum, supposing 

 the original expenditure on the present stock could be realised, which mast then be added 

 to the annual cost of the system. 



