44 



THE CIVIL ENGINEER AND ARCHITECrS JOURNAL. 



[Feb. 



The Commission aJds, that it will he better to have both engines cx- 

 artly alike, and that the principal point to he observed when two engines 

 are employed is, never to allow the hijulniost one to be driven at a greater 

 speed than the foremost, and also to take care that the driver of the front 

 engine has the driver of the other engine under his control. 



The next question discussed by the Committee was, whether, as regarded 

 safety, the position of the engine in front or bnliind the train was material. 

 With respect to this, it appeared evident that the engine-driver, if placed 

 behind '.he train, could not easily see what was going on in front, and that, 

 therefore, there would be great danger of his not perceiving any obstacle. 

 The Commission was therefore decidedly of opinion that the locomotive 

 ought never to be attached to the hinder part of the train. 



Having thus disposed of the questions relative to the engines, the Com- 

 mission inquired into the dill'erent plans employed for linking ihe carriages 

 together. There appeared lo he three : — The lirst consists of chains of a 

 wrtain length, leaving a certain space between the carriages, independently 

 of that allowed for the play of the springs. The second consists in the 

 employment of moveable bars, which also allow of the play of tlii' springs, 

 but unite the carriages more rigidly than the first plan. The third, and 

 last plan, consists in uniting the carriages rigidly together, by screws and 

 keys. 



On comparing these plans, the Commission remarked, that as regarded the 

 first, independently of the disadvantage it possessed of causing unpleasant 

 shocks in starling, serious accidents might be occasioned, in the case of a 

 violent shock, by permitting the carriages to run over each other. It was, 

 therefore, considered that the best mode of uniting Ihe carriages would be 

 by rigid fastenings acting upon springs. By this means, in case of a 

 collision, the train would ofier the resistance of a solid mass, and there 

 would be no danger of the carriages running over one another. 



The only disadvantage of this plan would be, requiring more power 

 from the locomotive; but this is a minor consideration, when the safely of 

 the passengers is concerned. The Commission was therefore of opinion, 

 that the carriages should be united in such a manner as lo allow of ihe 

 bull'ers being always in contact. 



Another no less important question was, whether vehicles with cast iron 

 wheels ought to be allowed between the tender and the passenger car- 

 riages. This was decided in the negative, as it appeared that cast-iron 

 ■wheels, running with great speed, would soon wear, and were liable 

 to break ; iu which case, the train would be almost sure lo be thrown oil" 

 the rails. 



The Commission having thus decided upon the best means of forming 

 the trains, as regarded Ihe safety of the passengers, the subject next to be 

 considered was the best means of regulating the speed of trains, and free- 

 ing them as much as possible from danger of accident, to which ihey 

 might be exposed. 



The most usual causes of accidents may be resolved into one, viz., a 

 sudden shock, produced either by the locomotive coming into contact wiih 

 some obstacle ; by the breaking of an axle; or by ruuniug olT the rails. 



As reganls Ihe breakage of axles, accidents likely lo occur therefrom 

 may be most readily prevented by the promptitude and intelligence of the 

 engine-driver. 



With regard to shocks and sudden stoppages, what tends most to in- 

 crease the danger is the speed at which the train is travelling ; in order 

 therefore either wholly or partially to obviate them, it is desirable lo lind 

 (Hit the best means of slackening the speed at pleasure. For this purpose 

 Ijrakes are used, which act by pressing on the periphery of the wheels of 

 one or more carriages of the train, and by that means diminish the speed. 



The brakes most commonly u.sed upon railways may be divided into 

 three classes. — 1st. Brakes acting on one wheel only of each axle, and 

 pressing on one side of the wheel. — 2ud. Brakes acting on one wheel of 

 each axle, but pressing against both sides of the wheel. — 3rd. Brakes 

 acting on both wheels, and on one side of each wheel. 



Neither the first nor the second ought to be used, as they have a tendency 

 to dismount the wheel opposite to that on which they act ; and the first, 

 especially, has a tendency to destroy tlie parallelism of the axles, which 

 might occasion serious accidents. 



The third class of brakes possesses neither of these inconveniences. It 

 is true thai, by acting on one side of the wheel only, the whole of the 

 pressure will be exerted upon the pivot of the axle ; and although this 

 pressure is equal lo the weight supported by the wheel (and coosi'quenlly 

 the pivot of the axle does not sustain much more strain ihau under ordi- 

 nary circumstances), the best plan would no doubt be that by which a pair 

 of wheels would be acted upon on both sides simultaneously; tiie ellurts 

 of inventors should therefore be directed to this object. 



With regard lo the brakes now in use upon railways, the Commission 

 ■was not sutiiciently informed upon the subject to be able to recoinnieud 

 any one of the proposed plans, and it appears that careful experiments 

 would be necessary to decide the question. The following are tlie facts to 

 be considered in these experiments ; — 



1st. M' hat is the time necessary for enabling the person having the ma- 

 nagement of the brake to produce suflicienl pressure on the wheels to slop 

 them, including the lime necessary for signalling? 



2ud. What is the time necessary to elapse, and what distance will have 

 been travelled, before a carriage, travelling at vaiious speeds and provided 

 with eflicieut brakes, can be stopped 1 



This experiment ought to be tried many times, under various atmospheric 

 t ■odeucies, in order lo test the etl'ecls of dryness, dampness, or hoar-frost, 

 or the eil'ect of Uurowiug sauU oa the raib, as vviis proposed and pracUaed 



on the railway from Saint Etienne to Lyons ; the experiments should be 

 made upon levels as well as inclines. 



Srd. M hat is Ihe time necessary to elapse, and the distance to be run 

 over, in order to stop a train composed of a locomotive and lender, and 

 six or eight ordinary carriages, on different inclines and under various at- 

 mospheric influences, the carriages being provided with brakes, and driven 

 at various speeds, making use, — 1st. Of the tender brake, the steam being 

 shut off. — 2nd. ()f one, two, or more of the carriage brakes, the steam 

 being shut off. — Srd. Of all ihe brakes, and reversing Ihe engine; in fact, 

 employing all the means known for slopping. — The Commission, in con- 

 sidering the question as to the propriety of skidding all the carriages, is of 

 opinion that it would perhaps be advisable, when proceeding at a speed of 

 from twenty-five lo thirty miles an hour, to adopt Ibis method ; but generally, 

 in a train composed of a locomotive, tender, and seven or eight carriages, 

 only one of the carriages is provided with a brake, and the Commission 

 wished to ascertain which carriage it should be applied to. 



It was remarked that, independently of the momentum acquired by the 

 carriages respectively, each of ihem is, at the time of stopi>ing, pushed 

 forward by the one behind it, especially when connected loosely by chains ; 

 it therefore appeared advisable to provide the lust carriage with a brake, 

 which should act at the moment of stoppage, and, by ihus offering a re- 

 sistance, the force of which may be mathematically calculated, tighten the 

 connecting chains or rods of the front carriages. 



Should any apparatus be used to deaden shocks? And if so, what po- 

 sition ought it to occupy? 



On this subject, ihe Commission is of opinion, that if it were possible to 

 throw the whole or Ihe greater part of the force of the shock upon any 

 inert body, the safety of the carriages would be much increased; and as 

 lo the place it ought to occupy in the train, Ihe Commission considers it 

 best to place the brake between the tender and the passenger carriages. 



Several kinds of apparatus adapted for this purpose, were presented. 

 Some of them were composed of metallic springs, which would be gra- 

 dually compressed by the shock, and by that means slacken the speed of 

 the train ; and others were composed of air-springs acting upon the same 

 principle. 



With regard lo Ihe former, they would be the more effieacions, in pro- 

 portion lo the lime they allowed Ihe train lo run while compressing the 

 springs ; but, at the same time, the length of the springs must not be such 

 as lo cause danger of runniug off Ihe rails when traversing curves. On 

 the other hand, it will be understood, that it is advisable to construct them 

 so as to offer the greatest possible degree of resistance; their weight must 

 not, however, be greater than that of an ordinary loaded carriage. In 

 order lo produce the desired effect, the apparatus should be so constructed 

 as lo allow the train to bear the greatest possible compression without in- 

 jury ; occasion no danger in traversing curves ; and olfer the greatest pos- 

 sible resistance niih Ihe least weight. 



With regard to the air apparatus, it would not act efficiently unless made 

 of very large dimensions, so as lo present a large body of air to be com- 

 pressed ; this kind of buffer is therefore inadmissible, from its bulk. In 

 fact, as the density is in an inverse ratio to ihe volume of air, the apparatus 

 would not act until Ihe piston, meeting w ith resistance from the air, would 

 be nearly at the end of its course, at which point it would not offer any 

 efficient resistance to a shock of any considerable violence. 



It appeared lo the Commission, that an apparatus offering great resist- 

 ance would not act so ellicienlly as one which would be broken by the 

 shock of a collision. 



It was thought that it would be advisable to propose a prize to the In- 

 ventor of any apparatus, which, after being in use for some time, was 

 found lo act eflicieully. 



There are some preliminary arrangements, as regards safety, to be con- 

 sidered. One precaution which has been adopted consists in interposing 

 between the tender and the passenger-carriages as many empty carriages 

 as there are locomotives : this precaution may, in most cases, preserve the 

 passengers from injury. 



IV. Of Rules to be enforced by Law in Working Railways. 



The first point lo be considered, as regards safely in railway transit. Is 

 the working with perfect regularity, aud subject to fixed rules, which must 

 never be infringed ; il is clearly tlie duly of Government to legislate on 

 this subject. 



By the present laws, railway companies are empowered to frame bye- 

 laws for working, but they are obliged lo submit them for Ihe approval of 

 the higher authorities. This is a salutary regulatiou, aud Ihe companies 

 ought lo be bound lo inform the Government, in good time, of the hours 

 fixed for the departure of the trains, as well from the termini as the inter- 

 mediate stations. 



Express trains must be used as rarely as pos.sible, and only when they 

 are absolutely necessary : their approach must be signalled along the line. 



The Commission has not given much attention to cases where accidents 

 might happen from two trains meeting ou the same liue. On railways, by 

 which a great number of persons travel, there are always at least two 

 lines of rail, and the only likelihood there is of one train running into 

 another, is when they are both travelling the same way ; and even this 

 might be avoided if the ollicials were to adhere to the times fixed by the 

 autliorities for departure from the termini, and those fixed by themselves 

 for Ihe intermediate stations. 



Independently of the shocks which may happen when the trains are in 

 moliuu, passeugera have aometinies been eenously injured from shocks 



