1840.] 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



.347 



*' Account of a scries of Experiments on Locomotive Engines, more par- 

 ticularly on the ' Enyland' the ' Columlia' and the ' Atlantic' mannfactiired 

 by Mr. Norris, of Philadelphia." By Captain Moorsom, R.E., Assoc. I.C.E. 



The engines of wliicli tlie author more especially treats were constnicted 

 by Mr. Nonis, of Philadelphia, and sent by him to England, under an agree- 

 ment to supply "locomotive engines of a higher power, greater durability, 

 and less weight," than could be obtained in this country. They were to be 

 subjected to fifteen tri.ls within thirty days, and prove their capaliility of 

 drawing " up a gradient of 1 in 330, a load of 100 tons gross weight at the 

 speed of 20 miles per hour ; and up a gradient of 1 in 180, a load of 100 

 tons gross weight at the speed of 14 miles per hour." The pressure of the 

 steam in the boiler was stipulated by the Grand Junction Company (on whose 

 railway the trials were made) not to exceed 60 lb. per square inch. 



The construction of these engines is very simple, and the work plain. The 

 boiler is horizontal, and contains 78 copper tubes, 2 inches diameter and 

 8 feet long each, with an iron fire-box. The cylinders, 10 V inches diameter, 

 are slightly inclined downwards, and so placed that the piston rods worii 

 outside the wheels, thus avoiding the necessity of cranked axles. The frame 

 is supported by 6 wheels ; the two driving wheels, of 4 feet diameter, are 

 placed close before the fire-box ; the other 4 wheels, of 30 inches diameter, 

 are attached to a truck, which carries the front end of the boiler, and is con- 

 nected with the frame by a centre-pin, on which it turns freely, allowing the 

 truck to accommodate itself to the exterior rail of the curve, and with the 

 assistance of the cone of the wheels to pass round with very little stress upon 

 the rails. 



Tons.C'wt. 

 The weight of the engine, with the boiler and fire-box full was 9 11} 

 That of the tender, with 21 cwt. of coke and 520 gallons of 



water, was 6 4} 



Total weight 



15 151 



The engine, when empty, weighed 8 tons. 



The trials were made on the Grand Junction Railway in April and May, 

 1839, and were continued over the whole distance from Birmingham to Liver- 

 pool, except when stopping short at Warrington to take loads ; and occasion- 

 ally making double trips, so as to travel the total distance of 156 miles per 

 day. Attention was more particularly paid to the speed when ascending the 

 gradients, which rise at the rate of 1 in 330 (16 feet in a mile), or 1 in 177 

 (29 ft. 4 in. per mile), and as the engines approached these gradients fre- 

 quently either at an accelerated or a diminished speed, the observations were 

 iiiade at the points most remote from the cause of variation from uniform 

 velocity. Some of the trials were made with such a number of empty wag- 

 gons to make up the weight, that the train attained a length of nearly an 

 eighth of a mile : this required some allowance, which was estimated at from 

 one-eighth to one-ninth in addition to the actual weight of the empty 

 waggons. 



The extreme limit of working pressure of the steam in the boiler was 

 62 lb. per square inch, except for a few minutes on one occasion, when it rose 

 to 64 lb. The usual piessure for the locomotive engine boilers on railways 

 now generally at work, is from 50 to 75 lb. per square inch. 



An analysis of the tabulated results of the several trips give these general 

 results : — that on a plane of 1 in 330, with a load varying from 100 to 120 

 tons, the speed varied from 13^ miles to 22 J miles per hour; that on a 

 plane of 1 in 177, with a load of 100 tons, the speed varied from 9^ miles 

 to 13-^ miles per hour. 



From the analysis it appears, that allowing in five of the trials the stipu- 

 lated amount of performance to have been made, and that in five otlier trials 

 a doubt may exist, still in the remaining eleven trials the exact amount of 

 duty demanded was not performed. 



A comparison of the journeys up from Liverpool to Birmingham, with 

 those down from Binuinghara to Liverpool, gives rather a singular result. 

 The aggregate rise of the gradients from Liverpool to Birmingham is about 

 €20 feet, that from Birmingham to Liverpool is about 380 feet (exclusive in 

 both cases of the Liverpool and Manchester Railway) ; the difference, there- 

 fore, up to Birmingham is about 240 feet. In 7 journeys of 596 miles up to 

 Birmingham, the engine conveyed 682 tons gross, evaporated 12,705 gallons 

 of water, and consumed 177 sacks of coke (l-j cwt. each). In 7 journeys of 

 596 miles down from Birmingham, the same engine conveyed 629 tons gross, 

 evaporated 12,379 gallons of water, and consumed 177 sacks of coke. It 

 •would thus appear that the consumption of fuel was the same in both cases, 

 and the only diflference was the evaporation of 326 gallons of water more in 

 the journey up than in the journey down, conveying nearly the same load both 

 ways. 



The author remarks, that in the early stage of his observations on the en- 

 gine, he would have inferred that, from the mode of construction, it was not 

 calculated for high speeds, such as are required for the mail trains ; yet that 

 he has often seen it travel with apparent ease at the speed of 30 miles per 

 hour ; and he thinks that, with some slight modification of the working parts, 

 engines of this construction may be made to do any duty now required from 

 locomotive engines ; and, from the small quantity of repair required during 

 the trials (only renewing the fire-bars, which were originally intended for 

 burning wood, and putting nine stronger ferules in the tubes), he is of opinion, 

 that the present construction is exceedingly well calculated for heavy loads — 



that it may be modified for attaining high speeds — and will prove a durable 

 and economical machine. 



Captain Moorsom, in reply to some questions from several members, stated, 

 that although the -American locomotive engines had not strictly complied 

 with the stipulated conditions, yet he considered them good, serviceable en- 

 gines, and it was the intention of the directors of the Birmingham and Glou- 

 cester Railway Company to have ten of them on their line. The price of the 

 engine complete, including the import duty of 20 per cent., is from £1500 to 

 f 1600. One of the greatest advantages of the engines is the facility afforded 

 by the truck for going round curves — the same engineers managing indis- 

 criminately the ordinary six-wlieel engines, and the American ones are ob- 

 served to go faster round the curves with the latter than with the former. 

 Round a curve of 10 chains radius, they had gone at a speed of 20 miles per 

 hour. They run also quite as well on a straight road, lie had travelled on 

 them between Whitmore and Crewe at the speed of from 30 to 40 miles per 

 hour. They appeared less likely to be thrown off the rails than other engines, 

 as in some instances they had run over the short pointers of the Grand 

 Junction Railway — the engineer had merely felt a slight jar, but no accident 

 had occurred. He attributed this to the truck adapting itself so readily to 

 the rails. The coke used in the trials was the same as that in daily use on 

 the Grand Junction Railway, and was of average quality. The mode of at- 

 taching the tender to the engine was peculiar, and lie conceived it to be ad- 

 vantageous, as it threw a portion of the weight upon the engine and was an 

 assistance in starting. The engines, as they are now constructed, will do 

 well for all ordinary speeds ; but if higher speeds are required, a greater ex- 

 pense must he incurred, and certain alterations must be made in them. 



Mr. Bury conceived tlie chief peculiarity of the engine to consist in the 

 end of the boiler being placed on the moveable truck, which certainly enabled 

 it to adapt itself easily to any curve in the railway. The cylinders are in the 

 same position as those in the first of Stephenson's engines, and the other 

 parts are as nearly as possible identical witli plain engines constructed in 

 England. The pointers on the Grand Junction Railway are constructed and 

 placed in such a manner as not to throw off a carriage which might run over 

 them, and a four-w lieeled engine would not have been thrown off by meeting 

 a closed pointer. To enable him to form a correct comparative estimate of 

 the work done by these engines, it should be shown what power was exerted 

 at the wheels. This was a clear mode of arriving at a result and comparison 

 with other engines. 



Mr. Dnnkin remarked, that the flanches on the wheels appeared to be all 

 that retained tliein on the rails, and that the truck turning on a centre-pin 

 would allow considerable lateral friction, unless there was some mode of 

 keeping the truck in a proper position when on a straight line of railway. If 

 this kind of engine is superior to those generally in use in this country, it 

 must be in some jiart of the construction which is not shown in the model or 

 by the description. He inquired whetlif r, in any of the four or six-wheeled 

 English engines, any provision is made for changing the position of the a.xles, 

 so as to allow of a divergence from parallelism when rounding curves. 



Mr. Bury replied, that in the engines on the Leeds and Manchester Rail- 

 way, although the axles were placed parallel to each other, a considerable 

 allowance was made in the journals of one pair of the wheels, so as to facili- 

 tate the passage round curves. 



The President observed, that the wheels being turned conically was of 

 much assistance in passing curves, even although the axles were confined by 

 the journals in a parallel position. He was aware that (his threw an extra 

 strain upon the curve rails, but that would only require more attention in 

 securing them than on the straight line of railway. 



" Model of the Coal Field of the Forest of Dean." 



Mr. Sopwith exhibited a model of a tract of 30 square miles of Gloucester, 

 shire, comprising the mining districts in the Forest of Dean. This model 

 showed all the undulations of the surface, the towns, villages, and detached 

 buildings, railways, coal and iron mines ; and separating vertically through 

 the centre from north to south, and from east and west, exhibited the geolo- 

 gical formation down through the coal measures to the old red sand-stone : 

 the construction is such that, by Ufting off horizontal layers, the extent and 

 position of each bed of coal is shown, with the extent of the workings in the 

 different collieries, and on each bed is marked the portion that can be worked 

 by level and freed from water by natural drainage. This coal tract forms an 

 elliptical basin ; the longest diameter of which, from N. N. E. to S. S. W. is 

 about 10 miles, and the shorter about 6 miles, ranging round Coleford as a 

 centre. There are about 20 beds of coal of various thickness, containing to- 

 gether nearly 37 feet of clear coal. The carboniferous strata crop out regu- 

 larly all round against the mountain lime-stone and old red sand-stone, and 

 dip uniformly towards the centre of the basin. This could scarcely be shown 

 clearly, even by an almost indefinite number of plans, which induced Mr. 

 Sopwith to project the model, the method of constructing which he described 

 to be by framing together in squares a given number of thin strips of wood, 

 joining them b^ half lapping at the intersections ; on these strips, the profiles 

 of the sections were drawn, from measurements and borings. The compart- 

 ments of these skeleton frames were then filled in with lime-tree wood, as 

 being lightest and easiest to work, and carved out to the depth of the lines 

 drawn on the strips ; by these means a series of horizontal sections fitting 

 into each other were obtained, and when painted of the proper colours, both 

 on the surfaces and on the edges, prodaced the complete model which he 

 exhibited. The cost of it was about iSSO complete. It was constructed un- 



3 A 2 



