316 



THE CIVIL ENGINEER AND ARCHITECTS JOURNAL. 



[OCTOBKH, 



rcctiy, the rubber, was then in proper operation. That experiment was tried 

 on the 19(b of November 1843. Sliortlj alter that we broke the apparatus; 

 it got worn out ; anil on Itie I3lh of January, wlien we had tlien been run- 

 ning a week without this apparatus, I found tliat tlie leakage was increased 

 to seven feet per second. Subsequently we restored that apparatus ; and I 

 happened to try another set of exjieriments on tlie Uth of March 1R44, and 

 the leakage liad come down to 3^ths; the so called heating apparatus, 

 therefore, makes an enormous difference in the leakage of the long valve. It 

 is erroneous to name it a heating apparatus ; for if it is heated, it destroys 

 the whole thing; the object of warming it is merely tn prevent the coniposi- 

 tion sticking to it a.s it passes over it; it is barely warm. If, by any aeci. 

 dent, the train rests for a moment, and this becouies heated, we are obliged 

 to send a man to relay the composition." 



Composition used for sealing the valve — {r.crr/in.) 



"iVIr. Gibbons mentioned an occasion on which it was necessary to change 

 the grease; I had that done last October or November; it was then done 

 throughout the line. I found that a very serious mistake had been made by 

 our foreman in using the wrong materials for the composition, and that in- 

 stead of making it of hees'-wax and oil, which was the direction given by 

 Mr. Samuda, he had made it of bees'-wax ami hard Russian tallow, so that 

 though it acted pretty well in the warm wealher of summer, it became in- 

 operative during the cold wealher. The mistake not having been observed 

 during the first part of the woiking year, a coiiMderable quantity of tli s 

 wrong composition had been put along the line. Being apprehensive of the 

 result, I directed that all the old composition should he taken out, and the 

 new put in, which occupied ten or twelve nights ; but ever since that, though 

 we have had the thermometer much below freezing, we have not had the 

 slightest interruption, whether it was wet or frosty. What is the nature of 

 the composition .' — I do not remember the proportions, but it consists of 

 bees'-wax and what is very well known in the London market as expressed 

 oil of larrl, elaine ; it is better known as lard. oil to the trade. Do jou find 

 that composition, from long exposure to the air, becomes ultimately less sus- 

 ceptible of change from the difTerence of temperature ? — I certainly find that 

 it undergoes very material change, which I did not at all anticipate. From 

 frequent working we have found that the composition becomes of a very pe- 

 culiar consistency ; I hardly know anything to compare it to, but it acquires 

 a degree of tenacity that I never saw in any other waxen composition before, 

 «nd adheres with great force both tn the leather and to the iron. I found 

 with the thermometer below freezing, it did its duty perfectly, and continued 

 quite soft." 



Long Lines. — The peculiar advantages of the atmospheric system can only 

 be developed on a long line, where the maximum velocity can be attained — 

 {Rolinson.) 



The atmospheiic system is perfectly applicable to very long lines ; there 

 may at present he some difficulties, hut there is no doubt experience will 

 overcome them — (Vigvolen.) 



It is doubtful whether the atmospheric system is equally adapted to long 

 lines as to short lines, with a large na'^senger traffic ; it is most probable that, 

 with experience and good management, it will become so. In very long 

 lines with great traffic a douljle line wouhl he preferable — {Cubitt.) 



Lvggage Trains. — There will be no large luggage trains, but they will he 

 subdivided so as to maintain nearly an uniform weight and speed for every 

 train — (^Samuda.) 



Hail Trains. — On the atmospheric system the mail trains mast be worked 

 at a very great expense — [Locke.) 



" If you take a railway 100 miles long, and consider that in the night the 

 mail train has to be dispatched ; take the case of the Grand Junction, with a 

 mail train leaving Birmingham at 11 o'clock at night, and another coming 

 up at three o'clock; if the line is 100 miles long, there are 33 engines at 

 200-horse power each, and they would require COOO-horse power to be ex- 

 erted for the purpose of carrying one train; and the attendance upon the 

 engines would be three mrn to an engine of that kind, two stokers, and a 

 fireman, which is 09 men, besides all the attendance to the valve and pump, 

 instead of one locomotive, with two men attending it, to carry that train 

 through ; I sny that in the night, for one or two trains, the atmospheric sys- 

 tem must be immensely more costly. I do not think that there is one rail- 

 way in the country that has not one or two trains passing along it in the 

 night; and for the purpose of carrying the mails it must necessarily have 

 those trains passing along it." 



Allusion to the oljection made by Mr. Locke as to the running of mail 

 trains at night on the atmospheric system — {Samvda.) 



" Mr. Locke assumed that one train would pass during the night, and that 

 the whole staff arrangements of tlie company would have to be brought out 

 for the purposes of that single train. I cnnctive, however, the most con. 

 venient way of working railroads, and the way most generally adopted, is to 

 send the greater number of the goods trains at nigbt ; and when we have 

 subdivided our goods trains, for the purpose of avoiding the gigantic trains 

 which now go, we shall have a distinct call for our night wnik upon such 

 lines, and not only so, but we make provision for it in our estimate ; we in- 

 troduce a relay of men for the purpose of carrying it out." 



II.MSTEN.^NCE Or RoAD : — 1. Ott the Atmospheric System. — 2. On the 

 Locomotive System* 



1. Calculation of the cost of maintaining an atmospheric line — (Samuda.) 



"The expense necessary for maintaining aline we find to be, first, the 



maintenance of the tube, and that we find requires a man a mile for the ordi- 

 nary traffic, which, if taken upon 12 trains per day, will give a cost of ibij. 

 per train per mile ; take it at C trains it gives 2i/. Then we have the com- 

 position to supply any material which may have become evaporated or wasted 

 from the groove, that is 15/. p' r mile per annuu' ; this, upon the same num- 

 ber of trains, will represent -4 of a penny, making a total charge of l-2-(f. 

 per train per mile, for the maintenance of the atmospheric main and groove 

 %vith 12 trains a day ; and if this be taken upon six trains a day, it increases 

 the cost per train per mile to 2-5^/. For six trains will be fd. ; for 12 trains 

 5(i. ; and fr.r 24 trains a day, 4rf., the price of coal taken at 10s. per ton." 



2. General cost of the maintenance of way upon locomotive line — {Stopheti- 

 son.) 



" The maintenance of the London and Birminirham railway was originally 

 let for 340/. a mile ; that was the estimate, including every species of respon- 

 sibility for slips of all kinds. Of that amount I imagine that not more than 

 150/. a mile has been spent in keeping the road in order in the upper works, 

 that is, the rails ; the rest has been absorbed in rejiairing the slips of cuttings 

 and embankments, repairing bridges, clearing out watercourses, fencing, 

 painting the iron-work of all the bridges over canals, and a great number (ff 

 things of that kind. The repairing of the North Midland was let by con- 

 tract ; that was merely the upper works of the railway, witli the bridges ; 

 there was no responsibility attaciied to the contractor for slips, consequently 

 it is more nearly a fair comparison of the cost of maintaining the rails in 

 good order; that was let at 119/. a mile. The Great North ol England line 

 is kept in repair by the Company; 1 do not think they let, and I do not 

 know what it costs ; but the maintenance of loeomolive lines of railway will, 

 in my opinion, sink down to about 120/. a mile. That is rather more than 

 the Midland is let for, but it greatly depends upon the material; when the 

 railway is in a clay country the subsidence goes on very rapidly for three or 

 four years, and then it gets stationary, the embankments and cuttings settle. 

 The 340/. included everything, sleepers and all. 



" In working a railroad we may take it for granted that in the course of 

 20 years the whole of the rails must be replaced. The wear of the rails de- 

 pends upon the weight of the engines, but lias been very much overstated, as 

 I will explain. The engines weigh 16 tuns ; some of the goods engines, that 

 go at an inferior rate of speed, weigh 18 tons, and even some passenger en- 

 g'nes Inn; but we will assume them to be 16 tons. If they are working 

 upon six wheels, supposing the weight to he uniformly distributed in the 

 first instance, that will give 2^ tons upon each wheel of the engine; but the 

 weight is not uniformly distributed amongst the wheels; the greater portion 

 of the weight is thrown upon the middle wheel, that is, the driving wheel ; 

 there is probably ''.}^ tons upon that, therefore there will be seven tons iiprn 

 the two. In a goods wagon running upon four wheels, we frequently have 

 six and seven and eight tons weight, which alone comes to two tons per 

 wheel for the eight tons; they frequently exceed that: sometimes they carry 

 10 tons, that is too much, but they will load them in that manner. A four- 

 wheel goods truck is by no means so long as the engine, because the length 

 of a goods truck is probably only nine feet, whereas the length of the engine 

 is double that. The motion upon the railway depends very much indeed 

 upon the distance between the extremities of the axles, that is, an engine 

 having axles 12 feet apart runs infinitely more steadily than a goods wagon, 

 which has axles placed only five or six feet apart; the goods wagon also has 

 the goods elevated, and certainly the quantity is considerably higher than it 

 is in the engine, and thereby the goods trains moving quickly along railways 

 do far more damage than the engines themselves, and the injury to the rails 

 becomes very much aggravated by high velocities ; and therefore that is one 

 reason why I maintain, that supposing the atmospheric system to be suscep- 

 tible of big! er velocities than the locomotive, it would give rise to a greater 

 wear ami tear, and instead of requiting only light rails, I give it as my de- 

 cided opinion, that in the end they would require rails fully as heavy, be- 

 cause the engines do not in my opinion do the most harm to the rails." 



Newcastle and North Shields Railway — (Xicholson.) 



" We ran, in the year 1S44, an average of 23 trains each way per day; and 

 in 1843, 22 trains. Not quite half-hour trains throughout the whole day ; 

 from 12 to 2 they are hour trains, hut excepting those tliey are half-hour 

 trains. I have kept a very accurate account for the years 1843 and 1844 of 

 the expense per mile. It 1843 it was G"75r/. per train per mile ; in 1844 it 

 was a fraction less, it was 6'73d. ; the length of the railway is 7 miles." 



North Midland Roilvay. — Calculations and estimates u-itha view of show ' 

 ing that /^e whole cost of working the North Midland line as a locomotive 

 line is than the bark interest or money had it been laid dow.s upon 

 THE ATMOSPHERIC PRINCIPLE — (Stephenson) 



" On a line such as the Midland. I apprehend they must have a dianietrr 

 of tube of 15 inches, therefore it would hardly admit of any reduction below 

 what Mr. Samuda has stated, if the otmospheric were applied tn that line. 

 That is a line of great thoroughfare, the trains ai'qnire great velocity and 

 carry heavy loads; the cost of the Midland locomotive power comes to 240/. 

 per mile per a'lnum ;* if we take 6,000/. a mile, which was Mr. Samudit's 

 estimate for a single line of atmospheric, at five per cent, as before, here is a 

 sum again exactly similar to the sum upon the Yarmouth and Norwich, ex- 

 cept that the application of the atmoipheiic system might, if it had been 

 contemplated origi"aliy, have reduced the cost of the original works, Int as 



* The 2Jn;. ppr trite for loromntive power on the M dlard is jn»t lour pi 

 the 6,0U0/. cost ot" Ihe atmosplierie line per mile. 



