The locomotive for the Eaton Railway (No. 4 in the table) was built as an example of a four-wheeled engine for use where the traffic was small and the gradient reasonable. With the exception of radial axles, it is fitted up precisely as No. 8. It has not, however, been altogether a success. From the data of its hauling powers, it will readily be seen that there is no deficiency in this respect; indeed, the maximum load handled exceeded all my expectations. In its working, for now nearly two years, nothing has gone amiss, nor has there been any trouble. On the contrary, the engine has on all these points given full satisfaction. But it is with regard to its effect on the road that I have my doubts. The running is steady enough, and 20 miles an hour has been attained without undue oscillation, yet nevertheless the road suffers as it never suffers under the six and eight-wheeled engines. The long and short of my experience is that I should not again recommend a four-wheeler except for very short distances and low speeds. Nothing but the experience I have had with this engine could have impressed so forcibly on me the very distinct advantages of such a radial action as I have adopted in my other locomotives, which enables them to go round a considerably sharper curve than the four-wheeler with an ease and absence of grinding quite remarkable, to say nothing of the saving to the road by the distribution of weight over more points. The relief seems to be by no means so much in the lessening of the weight per axle, which is not very great, as in the increased number of points of support. I am well aware this is not a new discovery, but it has come home to me with a practical force that leads me to insist somewhat strongly upon its importance.
The whole of the foregoing locomotives have been entirely made in my workshops, with the exception of the boilers and steel castings. The former have been chiefly supplied to me of excellent workmanship by Messrs. Abbott and Co., of Newark, and the latter by the Hadfield Steel Foundry Co., of Sheffield.
The last locomotive in the table (No. 5) is now being commenced, and will combine all the advantages of the previous ones in a less costly engine than No. 8 which was built specially with a view to see how powerful and fast travelling an engine could be put on the 15 in. gauge. No. 5, with its smaller wheel, is not very inferior in hauling power to No. 8, and the expense of the extra axle is saved. This is the engine that, if I had to build another for the Eaton Railway, I should certainly recommend in preference to the four-wheeled No. 4.
The wheels of such little locomotives, since speed is no object, should be kept as small as possible, and the stroke should be of the greatest length. The nearer the stroke can be extended to half the diameter of the wheel, the more successful will the engine prove on steep inclines. Good sand-boxes, front and back, of ample capacity are essential, but it is not advisable to fit any steam sanding apparatus, for, owing to the low position of the motion, a good deal of the sand will rebound into the joints and bearings, as I found by experiment.
Cabs on such small engines are to be avoided as unbearably hot in summer, dangerous in case of emergency, and inconvenient at all times on account of the contracted dimensions. A stout mackintosh is cheaper and far better for the driver.
A steam water-lifter is a convenience in frosty weather when the water supply above ground may be frozen up, but in summer the engine tanks get so hot from their proximity to the boiler that the water, which becomes lukewarm in the process of being raised by the lifter, is then very soon at a temperature which makes the action of the injectors precarious.
I may say that in all my locomotives I use Holden and Brooke’s restarting injector, which, after experiment with many types, I find takes the hottest water and is in all ways most reliable. I place brass wire strainers in both steam and water-supply pipes close to the injector, which is invaribly fixed below the tanks, so that when the injector is overheated the water will run through by gravity and cool it; a most important advantage.
No. 1. 1875. “Effie.” | No. 2. 1881. “Ella.” | No. 3. 1894. “Muriel.” | No. 4. 1896. “Katie.” | No. 5. | ||
Diameter of cylinders | 4 in. | 4⅞ in. | 6¼ in. | 4⅝ in. | 5½ in. | |
Length of stroke | 6 in. | 7 in. | 8 in. | 7 in. | 8 in. | |
Diameter of wheels | 1 ft 3½ in | 1 ft 1½ in | 1 ft. 6 in. | 1 ft. 3 in. | 1 ft. 4 in. | |
Length of wheel-base | 2 ft. 6 in. | 4 ft. 6 in. | 6 ft. | 3 ft. | 5 ft. | |
Number of wheels (all coupled) | 4 | 6 | 8 | 4 | 6 | |
Length over framing | 7 ft. | 8 ft. 8 in. | 10 ft. 9 in. | 8 ft. | 10 ft. | |
Overhang at each end | 2 ft. 3 in. | 2 ft. 1 in. | 2 ft. 4½ in. | 2 ft. 6 in. | 2 ft. 6 in. | |
Width over framing | 2 ft. 3 in. | 3 ft. 10 in. | 3 ft. 10 in. | 3 ft. 10 in. | 3 ft. 10 in. | |
Length of boiler | 4 ft. 6 in. | 6 ft. 6 in. | 8 ft. 3 in. | 5 ft. 8 in. | 7 ft. 8 in. | |
Diameter of boiler | 1 ft. 10 in. | 2 ft. 1 in. | 2 ft. 1 in. | 2 ft. 1 in. | 2 ft. 1 in. | |
Length of firebox (flue) | 1 ft. 9 in. | 2 ft. 3 in. | 3 ft. | 2 ft. 3 in. | 3 ft. | |
Diameter of firebox | 11 in. | 1 ft. 3¼ in. | 1 ft. 3¼ in. | 1 ft. 3¼ in. | 1 ft. 3¼ in. | |
Number of tubes (brass, 1⅜ in.) | 23 | 57 | 57 | 57 | 57 | |
Heating surface | 23 sq. ft. | 70 sq. ft. | 91 sq. ft. | 53 sq. ft. | 80 sq. ft. | |
Grate area | 1.25 sq. ft. | 2.12 sq. ft. | 3 sq. ft. | 2.12 sq. ft. | 3 sq. ft. | |
Capacity of tanks | 18 gals. | 50 gals. | 84 gals. | 49 gals. | 77 gals. | |
Working steam pressure per sq. in | 125 lb. | 160 lb. | 160 lb. | 160 lb. | 160 lb. | |
Weight in working order | 1 ton 3 cwt. | 3 tons 15 cwt. | 5 tons | 3 tons 5 cwt. | 4 tons 5 cwt. (?) | |
Co-efficient of adhesion at 145 lb. meanpressure | 3.6 | 4.7 | 4.5 | 4.9 lb | 4.3 (?) | |
Tractive power per lb. pressure incylinders | 6.2 lb. | 12.3 lb. | 17.3 lb. | 9.9 lb. | 15.1 lb. | |
If diameter cylinder2 = 1, ratioheating surface = | 207 | 425 | 336 | 356 | 381 | |
If diameter cylinder2= 1, ratiograte area = | 11.2 | 12.8 | 11.0 | 14.2 | 14.3 | |
Load (exclusive of engine) on level. | 15 tons. | 35 tons. | 49 tons. | 28 tons. | 44 tons. | |
(These are average working loads which can be considerablyexceeded on the easier gradients.) | up 1 in 100 | 9 tons. | 21 tons. | 30 tons. | 17 tons. | 27 tons. |
| up 1 in 50 | 6.4 tons. | 14.6 tons. | 21 tons. | 11 tons. | 18 tons. |
| up 1 in 25 | 3.8 tons. | 8.3 tons. | 12 tons. | 6.5 tons. | 11 tons. |
| up 1 in 12 | 1.8 tons. | 3.4 tons. | 4.9 tons. | 2.5 tons. | 4.4 tons. |
VI.
WAGONS AND CARS
The wagons first put upon my line measured only 4 ft. by 2 ft. inside. It soon became apparent, however, that a gauge of 15 in. could carry with safety a much larger vehicle. In fact it may be taken as a reasonable rule that the floor area of narrow gauge wagons should not be less than four times the gauge in length and twice the gauge in width. I have found such a wagon very handy for light work, but on the Eaton Railway I adopted an over measurement of 6 ft. by 3 ft. with 1 ft. 3 in. depth of side. The wheel base is, in all cases, half the length of the wagon. The larger wagon above described carries 16 cwts. of coal, and from 20 to 22 cwts. of sand, road metal, bricks, etc., and weighs about 7½ cwts., or one-fourth of its total gross loaded weight, i.e., it carries three times its own weight. The axles in this case are 2 in. diameter. For heavier loads I have made the wagons with 2¼ in. axles to carry 30 cwts. which is the standard I have finally adopted; and also with 2½ in. axles to carry two tons. Two of these last were built for the Eaton line, on which logs of timber up to 30 in. square and 60 ft. long have to be conveyed from the G. W. Railway to the Estate works. Each end of the log rests on a “timber fork,” which can be fitted on to any wagon, and in this way, not only timber, but any kind of lengthy goods can be carried with the greatest ease. My resident engineer at Eaton gave me an amusing account of the arrival from Messrs. Handyside & Co. of the ironwork for the coal store at Eaton. This included a number of long and awkward shaped pieces, and the foreman sent by this firm to erect the shed was in despair at seeing the toy wagons provided for the transport of pieces that with some difficulty had been loaded in the main line wagons. To his surprise the 15 in. gauge handled them with far greater facility than the 4 ft. 8½ in., owing to length being no drawback.