380 



THE CIVIL ENGINEER AND ARCHITECTS JOURNAL. 



[Sept/ 



ANALYSIS OF THE ItErOUT OF THE SELECT COMMITTEE ON 



ATMOSPHERIC RAILWAYS. 



The following analysis of llie Report of the Commiltccr of the House of Commons on 

 Atmospheric HailiVdys lias b' en collated in aipliabetical arrangement for facility of refer, 

 ence. The orrgina! document is admirably drawn up, and the excellent copious index 

 which accompanies it has materially assistej us in completing our abstract. 



Accidents. — Reasons for considering tliat there would be more risk of 

 accidents upon a tingle atmospheric line than upon a double locomotive line 

 — (Stephenso7i.) 



" I considered that question in the first instance, '^hen the matter was 

 brought before me very carefully, and I cerlainly came to the conclusion that 

 the intersection of the lines would be attended with more risks on that sys. 

 teiu than on the locomotive system with two lines ; I think the risk would 

 be considerably more ; I am aware that it has been proposed to make use of 

 what are called fixed points in the crossings at the stations, but if the car. 

 riages are to ran into a siding, or even to run past, which many of them must 

 do at the rate of 30 or 40 or SO miles an hour if this principle be adopted, I 

 say that the danger is very great. The risk of getting off the line is princi- 

 pally confined to those points at crossings. On locomotive lines we have no 

 accidents of any consequence away from those points leaving the stations, 

 the accidents are almost always where the points and crossings are ; those 

 require to be attended to by manual labour. I prefer that a great deal to 

 the system of fixing points as it is termed, that is, self-acting ; self-acting 

 machinery has been applied in many cases to these very things for 9 or 10 

 years. I have known them occasionly adapted to work by themselves; the 

 engine going in or out of the siding opened or shut the points as the engi- 

 neer wished ; it is veiy easy to construct an apparatus of that kind, but it is 

 practically useless, and it has been already abandonetJ. In the first instance 

 I tried it myself on the Birmingham line, but ;in the winter time, from a fall 

 of snow, and a severe frost after it, we found that the self.acting switches 

 were always wrong, and they got fixed and would not act at all, and there- 

 fore anything like a self-acting apparatus I hold to be in all cases extremely 

 dangerous ; and the fact is that all railway companies that I am aware of 

 have abandoned them. 



Reasons for forming the opinion that the atmospheric system does not 

 give greater safely than the locomotive ; at the same time there is no reason 

 for apprehending greater danger — (Lode.) 



" It appears to me that the only reason why the atmospheric system could 

 be supposed to give additional security consists in the connexion between 

 llie tube and the carriage, tlie tube tending to keep it in connexion with the 

 line. Now, there must be, as it seems to me, such a play between the piston 

 and the train, in order to allow for the inequalities of the surface, as to ren- 

 der any impediment upon the rail very likely to throw the train off quite as 

 likely as upon the present system of locomotives. 



" I think that the locomotive system has one great advantage, in point of 

 security, which many persons may think a reason against it, and that is its 

 weight; I consider that the weight of the locomotive is one great source of 

 security, in all cases where it is carrying passengers. I will give one or two 

 illustrations; I have known a very heavy rail, weighing about 70 lb. to the 

 yard, which had been put across the railway maliciously, cut in two by the 

 weight of the engine ; I believe if it had been a lighter carriage, it would 

 have inevitably thrown it oflf the line. That is one reason why I say that a 

 locomotive is a source of security, rather than of danger. Again, I should 

 say that in the case of most of the accidents that arose in the early part of 

 tlie working of railways, the vis inertia! of the engine and the tender had the 

 chief part of the shock when the trains had got otf the rails, and that saved 

 the passengers from what I would consider destruction. So much was that 

 considered to be essential, that the Government, the Board of Trade, ordered 

 that an additional carriage, besides the tender and engine, should be placed 

 in front to prevent the train being broken to piece. Now, I consider that 

 the efl"ect of the engine (which always takes the brunt of the ai-cident, — the 

 effect is broken, because the engine comes first) is not only to force away 

 any obstacle, but to resist the effect of tlie impetus upon the carriages that 

 are behind it ; I believe that if the engine and tender were not there, the 

 effect upon the first carriage would be as serious as it is now upon the engine, 

 the momentum being considered. 



"Do you suppose that the evenness of way could be as well maintained if 

 you had the passage of locomotive, as it could be if you had simply the pas- 

 sage of passenger and luggage wagons ?— No, I think not ; but still I would 

 give that answer with some limitation; it is very true that there would be 

 more stress upon the hlm-ks of the road by a heavy train than by light ear- 

 riages; but I do not think tlie wear and tear depends upon The mere weight 

 which has to be transported upon it, because the suhsiilencc, after every 

 shower of rain, and every frost, would be the same, whatever weight was 

 carried over it; and my opinion is, that tlie inequalities of the road are pro- 

 duced more by the clianges of the weather than by the effect of heavy weights 

 passing upon it ; and moreover there are frequently as many as eight tons 

 carried on one carriage ; and when you are carrying eight tons upon four 

 wheels, my opinion is that it has nearly as much effect upon the rail as the 

 locomotive, because in the locomotive the weight is more equal ; there is not 

 much more weight upon a locomotive with six wheels, than upon an ordinary 

 luggage wagon with four." 



Air-pump. — Objections to the expansive principle of the engines applied 

 to the air.pump on the Dalkey line ; variable resistance in the air-pump, 

 — {Robinson.) 



" In the details of the machinery, I conceive there are many objectionable 

 points. Of conrse, as a mere tbeoribt, I should speak with some hesitation res- 

 pecting them ; but two or three of them must be obvious to any person. In 

 the first place, circumstances, as I understand, compelled the constructors of 

 this line to place their engine at a considerable distance from the main. The 

 connecting pipe, which connects the main with the engine, is about a fifth 

 of the whole capacity of the main. If the apparatus, the connecting tube 

 and the air.pump, had been, as they ought to have been, air tight, that would 

 not have been material; for it would have been a store of vacuum, a store of 

 power laid up for a subsequent emergency ; but as it is, one-fifth of the total 

 power expended in producing the vacuum is lost at every train, in conse- 

 quence of this connecting pipe." 



Arches. — The height of the arches on atmospheric lines may be reduced, 

 as there will be no engine-funnel to pass under them. 



Atmospheric Resistance. — The late arrival of trains on all raihvavs has 

 arisen mere from wind than anything else — {Stoptieiison.) 



Axles of Engines and Carriages. — In the event of a fracture of the axle of 

 a carriage, it could be removed from the line in five minutes — {Samiida.) 



During the seven years that the London and Birmingham line has been 

 open, and 10,000,000 of miles have been traversed, there have been but two 

 accidents from the breaking of the axles of engines. — There is no reason to 

 believe that the amount of accident would be diminished by the atmospheric 

 system, as far as regards the breakage of axles of carriages ; the result would 

 probably be the same, supposing there to be no engine — {Stephenson.) 



Brealis. — Carriages stopped by using powerful breaks: it is necessary, from 

 the high velocity required, to have a break with a guard to every second 

 carriage, on the Dalkey line — {Samudu.) 



Bridges. — The bridges over the South Devon line, which is an atmospheric 

 line, are of a less height by 18 inches than on locomotive lines; and those 

 under the railway are of less substance and strength than usual, as the weight 

 and vibration of the engines will be removed, and all the bridges and viaducts, 

 which are made of timber, are of a Ughter construction thau those on the 

 Bristol and Exeter railway. 



Coal. — Price of coal upon the London and Birmingham line ; probable 

 cost of coal if an atmospheric line were made from London to Birmingham 

 — Stephenson. 



" What is the price of coal upon the London and Birmingham line .' — The 

 coal is about 14s., the same price as you buy coals at in the London market ; 

 but they get some coals upon the line, at Rugby, at about 9s. or 10s. ; all the 

 coal that they buy at this end of the line of course costs them the same as 

 in the London market. If an atmospheric line were made from London to 

 Birmingham, the probability is that about lis. would be the cost of the 

 coal; I think that it is delivered now from the Derbyshire colleries at Rugby 

 at lis. a ton, and I do not think it could be materially reduced." 



Collisions. — On the atmospheric principle coUsions could not possibly 

 take place other than at the station ; with good regidations there is no rea- 

 son to apprehend danger at the stations — Lode. 



Connecting Rod. — In the event of the connecting plate breaking, the pis- 

 ton would proceed to the station without the carii.iges; another carriage 

 could then be sent, and a vacuum again created — Sam7:da. The connecting 

 rod between the piston and the carriage does not rub against the side of the 

 tube — Gil/bons. 



Con^rac/s.— Witness's brother estimated the' tubes at 4,000/. per mile; 

 they can be supplied at about 3,800/. — Samuda's Ev. 



Cost of Construction. — Relative expense of construction and maintenance 

 of the two lines — Vignoles. 



•' In almost all cases 1 think the expense of the construction of a single 

 atmospheric line will be less than that of a locomotive double line, when you 

 add the cost of the locomotive power and all the fittings relating to the lo- 

 comotive apparatus to tlie cost of the railway. I do not think I have any 

 tables here ; but the price of iron at this moment is so very high, that pro- 

 bably it would affect the question in some degree. If you take a double 

 locomotive railway per mile, laid down complete with 75 lb. rails, which are 

 now considered the best for locomotive lines, with the proportionate size of 

 chairs, the expense will vary from 5,000/. to G,000». a mile, according to the 

 price of iron. — Upon what lines have rails of that extreme weight been laid 

 down .' — On the Slidland Counties 75 lb. rails, and some of them 78 lb., and 

 there are cross sleepers. I was engineer for that railway. Is not the tendency 

 to make the rails heavier every year ? — Yes ; I proposed to put down 70 lb. 

 for the rails, but the directors said that they would take the advantage of 

 iron being cheaper, and would have rails laid down at 75 lb., and some are 

 781b. The cost of the upper works of a single locomotive line (that is, after 

 the railway is prepared to receive the bed of rails) will vary from 5,000/. to 

 6,000/. a mile. The London and Birmingliam cost, I think, on the average, 

 0,500/. a mile ; but then the price of iron was very high. I have laid down 

 lines of railway that have only cost 4,500/. a mile for the double line ; that 

 was when iron had got very cheap. The expense of workshops and every- 

 thing connected with that department is about 2,500/. a mile : it is ranch 

 more likely to be 3,000/. than 2,000/. Upon the Dublin and Kingstown 1 

 found the cost full 5,000Z., perhaps 9,000/. a mile ; but that was because the 

 line was only six miles long, and they have a large establishment of work- 

 shops. Ou the North Union it is about 2,000/. a mile. I have given the 

 variations iu cost dependent upon the price of iron and the weight of tbs 



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