242 



THE CIVIL ENGINEER AND ARCHITECTS JOURNAL 



July, 



by the exigencies of the peculiar locality where the engine worked. The 

 economical working of the engine was due partly to the attention and skill 

 of the driver, whs had become better acquainted with the capabilities of the 

 machine, had a better knowledge of the locality, and was stimulated by a 

 premium upon the saving of coke and other stores consumed, but was prin- 

 cipally to be attributed to the judicious alterations that had been made in 

 the construction. There had not been any reduction of the men's wages. 

 The usual pressure of steam was between 60 lb. and 66 lb. per square inch. 

 The weights of the trains varied considerably; they rarely consisted of less 

 than three carriages ; the heaviest he remembered weighed 93 tons, exclusive 

 of the weight of the two engines, which were employed to convey it up the 

 incline. He had not made any accurate experiments, as to the amount of 

 slipping of the wheels upon the rails, but with the ordinary traffic he did 

 not believe that any practical loss was occasioned by it. 



Mr. M'Connell stated that the pressure of steam in the boiler of the Ame- 

 rican engine, when the experiments were tried, was more than rOlb. per 

 square inch ; the spring balance was screwed down to 65 lb. pressure, and 

 as owing to the reduced speed of the engine, the steam was generated faster 

 than it could be consumed by the cylinders, and thrown off by the safety 

 valves, the pressure continued increasing. It should be understood that 

 Burv's engine, alluded to in the experiments, was intended rather for con- 

 veying trains at higher velocities, than for mounting the incline with a heavy 

 load, it was therefore labouring under a disadvantage. The steam ports in 

 the American engine were very large, and although steam was thereby wasted, 

 that arrangement was of material assistance, in the peculiar duty for which 

 the machine was intended. 



Mr. Braithwaite observed, that the quantity of coke consumed appeared 

 to exceed materially that upon other railways ; he understood that an engine 

 recently constructed by Messrs. Rennie used about 18 lb. per mile, and that 

 on the Liverpool and Manchester line, the average consumption was 16 lb. 

 per mile. It appeared to him that the real questions were, the absolute duty 

 performed with a given quantity of fuel, and at what cost i and also whether 

 the greater adhesion of the driving wheels was due to the weight impo ed 

 upon the engine, by fixing the water tank upon the boiler, and the coke 

 boxes upon the foot-plate, after suppressing the tender. 



Mr. M'Connell replied that the peculiar duty of these bank engines re- 

 quired the steam to be kept up for about 16 hours dad), during which pe- 

 riod they made eight trips, amounting in the whole to about 10 miles, of 

 which, during '20 miles onlj actual duty was performed, so that the greater 

 portion of the coke was consumed while the engines were at rest. When 

 they were running with luggage trains on the line the quantity of coke con- 

 sumed was very small. The difference of cost, in consequence of the various 

 alterations, and the improved mode of working the engine, was very great. 

 In January 1812, the cost per trip on the incline was 1 7s. 7x1., but in Jan- 

 nary 1843, it only amounted to 7s. 1 '.</. 



The average weight of the luggage trains was about 60 tons; two assist- 

 ant engines were used for heavy trains, merely as a precaution, in case of the 

 wheels slipping: otherwise one of the " Bogie" engines could perform the 

 duty alone, as with the passenger trains, which were always conveyed up 

 by the hank engine alone. 



Captain Moorsom said that the main question arising from this investi- 

 gation, was by what system steep gradients could lie worked with the great- 

 est efficiency, security, and economy; he would, however, in the present 

 case suppose the two former positions t,> be equal in both cases, and would 

 inquire only into the economy. 



It appeared from the returns of the London and Binningham Railway 

 Company, that the annual cost of working the Enston Square incline plane, 

 which was 1J mile long, with an average angle of I in 98, with stationary 

 power and an endless rope, was — 



In 1810 .. £2150 



IS II .. 1376 



1842 .. 1215 



On the Edinburgh and Glasgow Railway, the expenditure upon the Glas- 

 gow incline, which was about one mile in length, at an inclination of 1 in 42, 

 also with stationary power, was £ 1516 in 1842. He had understood (but 

 he could not produce authority for his statement) that, on the Great Western 

 Railway, the cost of working the Box tunnel incline alone, was, in 1841, 

 about £3500; and in 1842 it had been reduced to nearly £2500; that was 

 worked by locomotive power. Taking into consideration the number and 

 weight of the trains, their speed, and the relative length and the angle of 

 the inclines, he believed that the Enston Square incline might he said to 

 perform about half as much work as that on trie Lickey. 



Mr. M'Connell presented drawings of the locomotive after being altered, 

 of the detaching catch, and of the improved brake. After detailing some 

 important alterations made by him in the valves, as well as the substitution 

 of a different description of fire-bars and fire-frame, under an arrangement 

 by wdiich a considerable saving had been effected in the consumption of fuel, 

 he stated that, for several reasons, but chiefly to increase the adhesion of 

 the driving wheels of the engine, the tender had been suppressed, and a 

 large tank constructed to be carried on the boiler of the engine. It was 

 made of the best plate iron, J. inch thick ; its length was 8 feet Cl inches, 

 breadth 3 feet 5 inches, depth 3 feet at the sides, and 1 foot 11 inches at the 

 centre; the bottom was made to fit the form of the boiler, and was bedded 

 upon a coating of thick felt ; it was held in its place by four wrougbt-iron 

 straps passing round the boiler. Advantage had been taken of the waste 



steam, by introducing a copper pipe from the top of the fire-box dome, into 

 the upper part of the tank, carrying it, to and fro, from one end to the 

 other, with an opeu extremity to allow the escape of the steam into the 

 water; this pipe was furnished with a stop-cock; in addition to this a num- 

 ber of pipes were introduced from the smoke-box into the tank, by which 

 arrangement, the water in the tank was maintained at the boiling tempera- 

 ture, previous to being pumped into the boiler, which, in addition to the 

 saving of fuel, proved advantageous in diminishing the leakage and breakage 

 of the tubes and stays, arising from the sudden contraction by pumping in 

 cold water, when the steam was shut off while descending the incline. The 

 tank contained upwards of 400 gallons of water, a quantity sufficient for the 

 engine over 18 miles, and goods' trains had been taken the whole length of 

 the line (53 miles) by these engines with safety and economy. The supply 

 of coke was carried in sheet-iron boxes, each containing about 40 lb. weight, 

 and of a size to fit the fire-door of the boiler, ranged on platforms on each 

 side of the foot-plate, which platforms were fitted with boxes, to hold the 

 necessary tools required for the engines. 



Mr. M'Connell then described a powerful and efficient description of brake, 

 which be had constructed to act upon the driving wheels, it was so arranged 

 that the whole weight of the fire-box end of the engine could be thrown on 

 the wheel tires; one brake had been found quite sufficient to stop the engine 

 on any part of the incline ; from their position they were very easily brought 

 into action; the end working upon the fore part of the wheel, was connected 

 to a stud made fast to (he framing of the engine; the other end was worked 

 by a screw 1J of an inch in diameter, passing through a bracket fixed on the 

 boiler, which served as a nut. The main spring-plate of the brake was ren- 

 dered flexible by the wood blocks being in short segments, thus enabling 

 their entire surface to be brought into close contact with the periphery of 

 the wheel. 



A new form of catch, employed for detaching the engine from the train, 

 was described, it was stated to be managed with facility, and at the same 

 time was perfectly secure. The principal advantages of these engines wera, 

 he believed, the economy in the consumption of fuel, and the increased ad- 

 hesion of the driving wheels (the weight upon them being upwards of 10 

 tons, thus rendering the engine more effective in drawing heavy loads). The 

 expenses of repairs bad also been much decreased hj tin- improvements sug- 

 gested by practice. 



The following statement showed the comparative consumption of coke at 

 different periods, viz, : — 



for six months ending June 1841, 92-41 lb. of coke per mile run. 

 „ January 1842, si',- 



June ' 1312, 53-35 

 „ January 1313, 13-2 



March 7. — The President in the Chair. 



His Royal Highness Prince Allien was elected by acclamation an honoraiy 

 member. 



" On the causes af the unexpected breakage of the Journals of Rathea) 

 .tiles ; tintl on the twi ant <>/' preventing such accidents btj observing the law 

 of continuity in their construction." By William John Macqunm Raukine, 

 Assoc. Inst. ( I, E. 



The paper commences bj Mating that the unexpected fracture of originally 

 good axles, after running for several years, without an} appearance of un- 

 soundness, must be caused by a gradual deterioration In the course of work- 

 ing; that with respect to the nature an, I cause of this deterioration, nothing 

 but hypotheses have hitherto been given ; the most accepted reason being, 

 that the fibrous texture of malleable iron assumes gradually a crystallized 

 structure, which being weaker in a longitudinal direction, gives way under a 

 shock that the same iron when in its fibrous state would have sustained 

 without injury. 



The author contends that it is difficult to prove that an axle which, when 

 broken, shall be found of a crystallized texture, may not have been so origi- 

 uallv at the point of fracture, although at other parts the texture may have 

 been fibrous. 



He then proceeds to show that a gradual deterioration takes place in axles 

 without their losing the fibrous texture, and that it does not arise from the 

 cause to which it is usually attributed. From among a large collection of 

 faggoted axles which had broken after running between two and four \ears, 

 five specimens were selected, of which drawings are given, representing the 

 exact appearance of the metal at the point of fracture, which in each case 

 occurred at the re-entering angle, where the journal joined the body. The 

 fractures appear to ha\e commenced with a smooth, regularly. formed, miuute 

 fissure, extending all round the neck of the journal, and penetrating on an 

 average to a depth of half an inch. They would appear to have gradually 

 penetrated from the surface towards the centre, in such a manner that the 

 broken end of the journal was convex, ami necessarily the body of the axle 

 was concave, until the. thickness of sound iron in the centre became insuffi- 

 cient to support the shocks to which it was exposed. In all the specimens 

 the iron remained fibrous; proving that no material change had taken place 

 in its structure. 



The author then proceeds to argue, that the breaking of these axles was 

 owing to a tendency of the abrupt change in thiekness where the journal 

 met the shoulder, to increase the effect of shocks at that point ; that owing 



