In connection with this design of locomotive, the triumph of skilled mechanism, combined with the application of scientific research, deserves record, seeing that a troublesome waste product has been turned into a valuable calorific agent. We refer to the introduction of liquid fuel for locomotive purposes, as carried out under Mr. Holden’s patent.

Now, sanitary authorities have large powers, and they are very fond of abusing these powers, and pushing matters to extreme issues—although at times, as we know from personal experience, they sometimes exceed their statutory powers, and find themselves in a tight place from which they can only retreat by payment of compensation and heavy law costs.

In connection with the pollution of streams the authorities have very wide powers, and when they found the waters of the never clear or limpid Channelsea and Lea were further polluted by some oily, iridescent matter, with a pungent odour, the sanitary inspectors were soon ferreting out the offenders. The waste products from the Great Eastern Railway oil-gasworks at Stratford were found to be responsible for the nuisance, and the service of a notice requiring immediate abatement of the same was the result of the discovery.

Mr. Holden, remembering the good old proverb, “Necessity is the mother of invention,” soon commenced to experiment with the matter which the sanitary authorities refused to allow to be emptied into the already impure waterways under their jurisdiction. The result of a series of trials on, first a six-coupled tank engine, and then on a single express, was a four-coupled express engine on the G.E.R., No. 760, named “Petrolea.”

This locomotive was constructed in 1886, and in general appearance is similar to the four-coupled express engine just described. The heating arrangements are, however, supplemented by the liquid fuel burning apparatus, which may be briefly described as follows: The oil fuel is carried on this engine in a rectangular tank of 500 gallons capacity, but in later examples occupies two cylindrical reservoirs, which contain 650 gallons, placed on the top of the tender water-tanks, one on each side.

The liquid fuel is supplied to these reservoirs through man-holes at the foot-plate end. The feed-pipes from these tanks unite on the tender foot-plate at the centre, and from this junction the oil is conveyed by the flexible hose pipe to the engine, where the supply is again divided to feed the two burners situated on the fire-box front just under the footboard.

Both the liquid in the tanks and the injected air are heated before use, the former by means of steam coils in the tanks, and the latter by coiled pipes in the smoke-box. The heated liquid fuel and air are injected into the fire-box, through two nozzles in the form of fine spray, steam being injected at the same moment through an outer ring of the same nozzles. The steam divides the mixture of air and liquid into such fine particles that it immediately ignites when in contact with the incandescent coal and chalk fire already provided in the fire-box. The fire-box is fitted with a brick arch deflector.

The whole of the apparatus is controlled by a four-way cock fitted on the fire-box case, near the position usually occupied by the regulator. The positions of the cock in question are: (1) steam to warm coils in liquid fuel tank; (2) steam to ring-blowers on injectors; (3) steam to centre jets of ejectors; and (4) steam to clear out the liquid fuel pipes and ejectors. The success of “Petrolea” was so apparent and unquestionable that Mr. Holden’s patent system of burning liquid fuel was immediately fitted to other Great Eastern Railway locomotives, with the result that at the present time a number are fitted with his patent apparatus.

The following Great Eastern Railway locomotives have been fitted to burn liquid fuel:—

•   9 four-wheel coupled express engines.
•   6 single express engines. (Fig. 102)
•   1 six-wheel coupled goods engine.
•   1 six-wheel coupled tank, and
• 20 four-wheel coupled bogie tanks.

and the 10 engines of the new class of “single” bogie expresses. (Fig. 103.)

The application of the “Serve” corrugated tube has also been introduced on the Great Eastern Railway in connection with the liquid fuel. The goods engine and also two of the express passenger engines have the “Serve” tubes. The experiment of burning liquid fuel has been very successful, only 16lb. of oil having been consumed per mile run, against an average of 35lb. of coal per mile, with coal-fired engines.

Some very handsome Bogie Single Express Locomotives have recently been built at the Stratford Works of the G.E.R. Company to the designs of Mr. James Holden. They have been specially constructed for running the fast Cromer traffic. The boiler has a telescopic barrel 11ft. long, in two plates, and is 4ft. 3in. diameter outside the smaller ring. It contains 227 tubes 1¾in. external diameter, and the height of its centre line above the rail level is 7ft. 9in.

The fire-box is 7ft. long, and 4ft. ½ in. wide outside, and has a grate area of 21.37 sq. ft., and is fired with oil fuel. The total heating surface is 1,292.7 sq. ft., the tubes giving 1,178.5 sq. ft., and the fire-box 114.2 sq. ft. The working pressure is 160 lbs. per sq. in.

The driving wheels are 7ft., the bogie wheels are 3ft. 9in., and the trailing wheels 4ft. diameter. The total wheel base is 22ft. 9in., the bogie wheels centres being 6ft. 6in. apart, from centre of bogie pin to centre of driving wheel is 10ft. 6in., and from centre of driving wheel to centre of trailing is 9ft. The total length of engine and tender, over buffers, is 53ft. 3in.

The cylinders are 18in. diameter by 26in. stroke, the distance between centres being 24in. The slide-valves are arranged underneath, and are fitted with a small valve, which allows any water that may collect in the slide-valve to drain off.

Steam sanding apparatus is fitted at front and back of the driving wheels.

Macallan’s variable blast pipe is used, the diameter of the pipe being 5¼in., and of the cap 4¾in.

This variable pipe is being adopted on all the Company’s engines. The pipe has a hinged top, operated from the foot-plate. When the hinged top is on the pipe, the area is that of a suitable ordinary pipe, and when the top is moved off the area is about 30 per cent. larger.

It is found that a large proportion of the work of the engines can be done with the larger exhaust outlet, the result being a reduced back pressure in the cylinders and also a reduced vacuum in the smoke-box, and less disturbance of the fire and consequent saving of fuel.

The tender is capable of carrying 2,790 gallons of water, 715 gallons of oil fuel, and 1½ tons of coal. It is provided with a water scoop for replenishing the tank whilst running.

The weights of the engine and tender in working order are: engine, 48½ tons; tender, 36 tons; total, 84½ tons.

The oil-firing arrangements embody a number of ingenious details, among them the supply of hot air for combustion from a series of cast-iron heaters placed around the inside of the smoke-box, the air being drawn from the front through the heaters to the burners for the exhausting action of the steam-jets used for injecting the oil fuel. The latter is warmed before leaving the tender in a cylindrical heating chamber, through which the exhaust steam from the air-brake pump circulates.

The regulation of the oil supply is effected by a neatly designed gear attached to the cover and hood of the ordinary fire-door, and finally the burners or injectors are so constructed that should one require cleaning, inspection, or renewal, the internal cones can all be removed from the casing by simply unscrewing one large nut. These engines have polished copper chimney tops, and are painted and lined in the standard G.E.R. style, and fitted with the Westinghouse automatic brake.