Chapter III: Section IV: There were also problems relating to adhesion and friction, (2)

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.

NUMBER, DATE OF COMPLETION, No. 1. 1875. No. 2. 1881. No. 3. 1894. No. 4. 1896. No. 5. AND NAME OF ENGINE. “EFFIE.” “ELLA.” “MURIEL.” “KATIE.” 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 4 6 8 4 6 coupled) 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 23 57 57 57 57 in.) 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 125 lb. 160 lb. 160 lb. 160 lb. 160 lb. sq. in Weight in working order 1 ton 3 cwt. 3 tons 15 5 tons 3 tons 5 4 tons 5 cwt. cwt. cwt. (?) Co-efficient of adhesion at 3.6 4.7 4.5 4.9 lb 4.3 (?) 145 lb. mean pressure Tractive power per lb. 6.2 lb. 12.3 lb. 17.3 lb. 9.9 lb. 15.1 lb. pressure in cylinders If diameter cylinder2 = 1, 207 425 336 356 381 ratio heating surface = If diameter cylinder2= 1, 11.2 12.8 11.0 14.2 14.3 ratio grate area = Load (exclusive of engine) 15 tons. 35 tons. 49 tons. 28 tons. 44 tons. on level. (These are up 1 in 100 9 tons. 21 tons. 30 tons. 17 tons. 27 tons. average working loads which can be considerably exceeded on the easier gradients.) 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.

My standard wagons are constructed of pitch pine with angle-iron rims, and the box sides are framed together independently of the wagon itself, thus a flat wagon is converted into a box wagon by merely placing this frame upon it. These sides, or “tops” as they have come to be called, are about 15 in. deep, and the wagons being constructed to a standard size, are interchangeable. An iron rim on each enables two or three of the tops to be placed one above another upon any wagon, to give an extra depth. To empty the wagon, two men readily lift off the top, and, if necessary, turn it over sideways, sufficiently to shoot off the contents; or the load may be upset without removing the top. This mode is almost as rapid as emptying a tip wagon, which, though convenient to unload, is a fraud as to capacity, and cannot be designed to carry more than one-and-a-half times its own weight; and even then there is the objection that the centre of gravity is far higher than in the box wagon.

For carrying timber or other lengthy loads swivelling carriers can be placed on any two wagons; and if a greater length is required, these two wagons can be set a distance apart, with or without other wagons placed between them. By adopting the flat wagon as a standard, it is possible to adapt each one to any class of work, without the necessity of keeping a large variety for various purposes. A narrow gauge is said not to lend itself advantageously to the carrying of bulky material, but by loading a train of wagons without break from end to end, I clear hay off land, to which it happens that carts cannot have access, with great despatch. There is, therefore, no valid objection on this score. The cost of these wagons is from 80s. to 85s. per cwt. In the two years the Eaton line has been at work they have proved convenient in every way and show no signs as yet of wear.

In addition to a number of wagons, some of which are fitted with brakes, there are on my line seven bogie passenger cars and a bogie van; also a variety of miscellaneous stock, such as workmen’s car, screw and roller rail-benders, dynamometer car, and various small trolleys. The dynamometer car is constructed to indicate the tractive effort of the engine, the speed, and the distance travelled. The roller rail bender is worked by three men, two of whom work the winch which draws the rail through the rollers, while the third adjusts the pressure to produce the required curvature. The screw bender has two thrust blocks, opposite which works a horizontal screw, which straightens or bends rails with great accuracy, but in long or sharp curves the roller bender is more rapid and efficient, as elsewhere noted.

The passenger stock, which, like everything else, was built on the premises, requires a somewhat more detailed notice. There are four open cars, holding sixteen persons each, two abreast. These are 19 ft. 6 in. long and 8 ft. 6 in. wide, and are carried on two bogies of 1 ft. 6 in. wheel base, the total wheel base being 16 ft. 6 in. A foot brake is fitted to one bogie on each car. The weight of these cars is 20 cwt.; they therefore only weigh 1¼ cwt. per passenger seat, and reckoning sixteen persons to the ton, the proportion of live to dead weight is as 1 to 1. On the main lines it is more than 1 to 5. The cost of these cars, stained, varnished, and lined with linoleum, was £37 each.

In order to demonstrate the capabilities of even so small a gauge, a closed car of the same dimensions as those already described was constructed, which has doors and windows of the usual kind. Lest it should be supposed that the space is unduly cramped, I may mention that a visitor 6 ft. 3½ in. in height, when seated, found ample clearance for his tall hat. The cost of this car was £67, and the weight is 24 cwt. Here the proportion of live to dead weight is as 5 to 6.

As a further test of the capacity of a 15 in. gauge, I have built a dining car and a sleeping car of the same dimensions as the cars already described. The former seats eight persons and carries a suitable cooking stove in a compartment to itself. The latter contains four berths 6 ft. 6 in. long and 1 ft. 10 in. wide, with a lavatory and other fittings. This, though hardly an essential accompaniment to a line under one mile in length, can be utilised as an overflow bedroom for my boys when the house is full of guests. I am unable to state the exact cost of these two vehicles, but exclusive of fittings, it is little, if at all in excess of that of the closed car already quoted. The weights are somewhat greater, owing to the bogie truck frames being of cast iron instead of elm.

A closed luggage van, 15 ft. in length, but otherwise of the same pattern as the cars, concludes the list, and is used to convey luncheons, teas, etc., for large parties, to the station where refreshments are served. The extreme height of the closed cars is 6 ft.

All the wagons and cars are carried on chilled iron wheels, 13½ in. diameter, cast in my foundry. The axles, as has been stated, vary from 2 in. to 2½ in. in diameter, and on to these the wheel on one side is forced by a hydraulic pressure of about 15 tons, while the opposite wheel runs loose to reduce the curve friction. The journals run in cast-iron boxes, which are lubricated by sponges placed in oil receptacles below. The horn-blocks and axle-boxes, with a rubber block between them to form the spring, and a cover to the oil reservoir, are secured together by a single bolt, after the insertion of which no part can come loose. The castings are put together as they come from the foundry, without machining or fitting of any kind, the axle bedding well into the cast-iron box after a few days’ wear. For the Eaton railway, however, I bored out the boxes, but have not found any advantage to result. These bearings require oiling only at intervals of several weeks, and although some of them have been in use more than eighteen years, there has been no case of heating or other failure. The cost of each complete bearing, including horn-block box, cover, spring, and bolt, is only 5s., 1s. of which goes for the rubber.

The buffers and couplings are central. A single east-iron buffer, which in the case of the cars is mounted on a spring draw-bar, has a coupler of the same metal hinged to it by a bolt. The latter is self-coupling or not as desired; but, when turned back so as not to couple, the driver can, by bringing the buffers smartly together, cause it to fall and couple up. These couplers allow the wagons and cars to be shunted out of the train, when the engine is either pushing or drawing, by a quick manipulation of the points, the hook sliding laterally from its hold as the vehicles diverge on different lines. I designed some cast-steel coupler-buffers of this type lately for the Royal Engineers’ 30 in. gauge experimental field railway, near Chatham, which, though for reasons unconnected with their construction not adopted, are reported as the only ones of several types experimented with ‘which fulfilled the necessary requirements. In the bogie stock the coupler-buffers are fitted to the bogie, and not to the car frame, on account of the severe curves. In the construction of the wagons and cars almost every part is made to gauge, and put together without fitting.

The aim throughout has been to make the details of all the rolling-stock as simple, cheap, and efficient as possible, which has been principally achieved by adopting designs and modes of construction largely at variance with commonly accepted notions. The totally different conditions under which minimum-gauge lines work, as compared with ordinary railways, renders this possible without any sacrifice of safety or durability.

In Section IV. mention was made of tip-wagons supplied as an experiment to the Eaton line. These consist of steel tubs, U shaped in section, hung at each end on two trunnions riding in cast-iron pedestals, the latter being bolted to an under-frame of channel steel fitted with cast iron ends rivetted in, and so formed as to carry a drawbar with rubber cushions, to the end of which the coupler-buffer is attached. These wagons cost £20 as against £12 for the standard box wagon. They weigh 11½ cwts., and carry about this weight of coal, or a little more. Loaded with coal, they average a trifle under 24 cwt., exactly the same as the box wagon, which weighs 7½ cwt., and carries 16 to 17 cwt. of coal. Thus the paying loads of the two are as 3 to 4 for the same hauled weight. For short distances, where the emptying bears a greater proportional relation to the running time, or where the load must be got rid of in a particularly short space of time, tip-wagons may answer. For such purposes as my experience has had to deal with, they are a drawback, which, as I have previously pointed out, is increased by their inadaptability to the carriage of bulky goods. One of my strong contentions is that, on a small line, to avoid expense in rolling stock, every vehicle should be available for every purpose.

VII. THE DUFFIELD BANK WORKSHOPS.

A BRIEF account of my little works will be of some interest to engineers. I have already, in Section I., given an outline of my progress as a mechanic.

I will now describe the machinery by which the locomotives, carriage and wagon stock, and permanent way fittings have been constructed.

The machine-shop contains an 11 in. lathe for wheel turning, cylinder boring, and the heavier work; an 8 in. lathe for surfacing, sliding, and general work; a 7 in. lathe for screw-cutting and fine work; a 4 in. Pittler universal lathe, with a variety of automatic and other fittings, chiefly used for the smaller brass work, such as cocks, glands, lubricators, &c.; a 3 in. sliding and screw-cutting lathe, for very light work; a planing machine to take work 4 ft. by 1 ft. 6 in. by 1 ft 6 in.; an 8 in. stroke double-table shaping machine, fitted for hollow and circular shaping, specially used for machining coupling rods, &c.; a 4½ in. shaping machine with circular motion, for light work; a milling machine; a 9 in. stroke slotting-machine with compound table, for heavy work; a 2½ in. spindle drilling and boring machine; a 1¾ in. drilling machine, for general work; a screwing and tapping machine, to 1½ in. for bolts and to 2 in. for pipes; a cold-sawing machine, to cut iron up to 2¼ in. square; a slot drilling machine; a twist-drill grinding machine; two grindstones, three bench vices, and complete sets of screwing tackle and fitters’ tools.

The smith’s shop contains two fires, of which one is blown by a fan, and is suited for the heavier work; anvils for ordinary purposes and also for the treatment of angle iron, &c.; a 2½ cwt. gas hammer; a punching and shearing machine; a bench vice, and complete set of smiths’ tools.

The erecting shop contains an overhead travelling crane; an engine pit; a 30-ton hydraulic press for putting axles into wheels, crank pins into cranks, testing samples, &c.; a hand screwing and tapping machine to ¾ in. for bolts and to 1 in. for pipes; standards for fitting up frame-plates; a rivet heating forge; two bench vices, and tools for tube extracting and other special processes connected with the construction and repair of locomotives.

The iron-foundry contains a 16 in. cupola worked through a double tuyère by a “Root’s” blower; an overhead travelling crane; a core stove; charge-weighing scales; a large supply of boxes for general purposes, and special ones for cylinders, chilled-wheels, sleepers, gutters, &c., with all ladles and other appliances suitable for producing castings up to half-a-ton weight. Especial pains have been taken to turn out chilled wheels (13½ in. diameter), for the rolling stock, of perfect smoothness and of even depth of chill.

The brass foundry contains a furnace, a metal moulding bench, and the usual fittings.

The carriage shop has two lines of 15 in. gauge formed of cast plates bolted together and bedded in concrete, and contains a wood-morticing and boring machine; fitters and joiners’ vices, with every convenience for erecting, finishing, and painting two of the long 20 ft. bogie cars simultaneously, or eight of the standard wagons, according to requirements; all bulky joiners’ and carpenters’ work is also done in this shop.

The pattern and joiners’ shop contains a 5 in. Holtzappfel lathe; and a small circular saw; 2 instantaneous-grip vices; saw tooth-setting machine; and a variety of other special appliances, in addition to a full set of joiners’ tools.

The saw-shed contains a 30 in. circular saw bench; a band saw; a small general joiner; an 11 in. planing machine, and a small emery grinder.

The engine house contains an 8 horse-power Otto gas-engine, of which the water circulation is effected by a small centrifugal pump.

The drawing office is fitted up with the usual appliances, and is in telephonic communication with my house and two of the stations on the railway.

The general stores comprise timber; foundry sand of various qualities; five kinds of pig iron; copper, spelter, tin, &c.; bar, rod, and angle iron; wrought-iron tubing up to 2 in.; bolts, rivets, nuts, and pins; steam fittings of all kinds; every sort of requisite needed in the construction of small railways and rolling stock, and also for meeting house and farm requirements.

The pattern store contains patterns for all the locomotive, carriage, wagon, signal, permanent way, and general experimental work; and for drain grates, gutters, &c. which are supplied from Duffield for my other estates.

The shops are lit by gas, and the 15 in. gauge line runs throughout. The construction, both in wood and iron, is done as far as possible to template, and every endeavour is made to turn out the very best work, which is perhaps the more easily attained in that there are no profits to be considered. At the same time it should be explained that the shops and machinery are, throughout, though good and sufficient for their purpose, in no way models of excellence. Their object is only to turn out the chiefly experimental work required, and the gradual additions that have been made during the twenty-five years of their existence have been done as cheaply as was consistent with efficiency.

Outside the shops are a weigh-bridge for weighing rolling-stock and loads, and a six-ton crane to tranship heavy goods from drays to the 15 in. railway.

Adjoining the workshops is the locomotive shed, with rails raised 30 in. above the floor, so as to get more easily at the lower parts of these small engines. It is arranged for two locomotives, and is fitted with an air jet for raising steam, and with a water supply.

The carriage and wagon stock is, for the most part, housed in three sheds at various stations on the main part of the railway, 80 ft. above the workshops.

VIII. SCIENTIFIC CONSIDERATIONS.

THE present section contains the result of experiments and experience on points which, for the most part, are of interest only to those who study the scientific side of railway work. I here take the opportunity of placing on record various considerations, more or less connected with the subject of narrow-gauge railways, of too technical a nature to be mixed up with the descriptive pages. This explanation will account for the somewhat disjointed nature of the statements which follow.

The fact that narrow gauge locomotives are usually required to surmount much steeper gradients than are generally to be found on standard railways, makes adhesion a question of the first importance. It is very generally supposed that the co-efficient of adhesion between a wheel and a rail is a constant fraction of the insistent weight, varying slightly with the molecular structure of the metals in contact. There is, however, reason to believe that it decreases considerably with an increase of weight. In locomotives of the standard gauge, with from 12 to 18 tons per driven axle, it is generally held that a co-efficient of adhesion of one-sixth is all that can be counted on with certainty. From a number of experiments on the Festiniog Railway, with the results of which the late Mr. Spooner, who himself supported the theory, was good enough to supply me, I found that the load there per driven axle was five tons, the co-efficient averaging about one-fifth. Again, with my small engines that have a load on each axle of from 1.2 to 1.6 tons, the calculated co-efficient is two-ninths, in support of which I give the following experiment, conducted in the presence of two gentlemen belonging to a firm of locomotive builders, when it was under consideration to build for military purposes some engines on the plan of the No. 2 described in