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[as described in the October 1934 edition of the “in-house” LMS Magazine.]
SEVENTY 4-6-0 Superheated Mixed Traffic
Tender Engines are to be built under the 1934 programme. Fifty of these will be constructed by the Vulcan Foundry Co. and the remainder at our Crewe Works.
The engines will be numbered as follows:
20 engines built at Crewe 5000 to 5019
50 engines built by Vulcan Foundry Co. 5020 to 5069
The general appearance and principal dimensions of this class of engine, which has been designed for general utility, are shown on the accompanying photograph and diagram.
A Belpaire type of boiler with a taper barrel and a working pressure of 225 lbs. sq. inch has been provided and with a view to reducing weight, 2% nickel steel plates have been used.
A superheater is fitted, and the main regulator has been incorporated in the superheater header in the smoke box. A steam manifold (with a main shut-off valve) is provided on the top of the firebox doorplate in the cab, on which are attached the valves for the ejector and steam brake, injectors, carriage warming, whistle, pressure gauge and sight feed lubricator to regulator. The feed water is supplied through top feed valves provided on the second boiler barrel ring with water distributing trays.
Two pop type safety valves (2½ in. diameter) are fitted at the crown of the firebox. The firedoor is of the standard sliding type with a screen to prevent glare from the fire. An exhaust steam injector (10 mm. cones) is fitted on the fireman's side and on the other side a live steam injector (10 mm. cones) is fitted. Other boiler mountings
such as the water gauge frames and protectors, etc., are of the Company's standard type.
The two cylinders are carried outside the frames and are 18½ in. diameter x 28 in. stroke. Walschaert type motion is fitted, the valve travel being 6½ in. The piston valves, cylinders, piston rod packing and valve spindle bushes are provided with mechanical lubrication, while the oil to each piston valve is steam atomized. The mechanical lubricators are of the Company's standard type.
The coupling and connecting rods and motion are of high tensile manganese molybdenum steel. The connecting rods are of fluted section but the coupling rods are of rectangular section.
Wheel centres are steel castings with the wheel rim of triangular section and the tyre fixing is of the "Gibson" retaining ring type. The balance weights for the coupled wheels are built up by steel plates on both sides of the spokes, and riveted, the requisite weight being provided by filling in between the plates with lead.
The axleboxes for coupled wheels are steel castings with pressed-in brasses with suitable white metal crown and oil grooves provided on both sides of the crown to ensure a thorough distribution of oil to the journal.
The coupled axleboxes are arranged so that the oilpads can be examined by sliding out the underkeep while the axle box is in position. Each of the axleboxes is provided with a dust shield carried on the inside face of the box.
A mechanical lubricator supplies the coupled axleboxes, each of which has an independent oil feed to the crown of the box, with the standard back pressure valve and flexible oil pipe connection.
All the laminated bearing springs for the engine and tender are made of silico manganese steel, the plates being of a ribbed section and with the cotter type fixing in the buckle. The spring links are of the screwed adjustable type.
The four-wheeled bogie is the standard type, the weight being taken through side bolsters, and the bogie side check spring gear is provided to ensure smooth riding.
The width over the cab is 8 ft. 6 in. All controls are arranged for convenient handling and tip-up seats are fitted on each side of the cab. Two sliding windows are fitted on each side and hinged windows on the cab front plate. A small hinged window is provided on each side to act as a draught preventer for the enginemen when looking out.
Steam brake is provided on each of the coupled wheels and operated by the driver's vacuum brake valve. A vacuum pump driven from the crosshead is fitted on the left-hand side of the engine.
The sanding is of the mechanical trickle type, the sand being delivered to front of leading coupled wheels, or front and back of middle coupled wheels.
In addition to this a water de-sanding apparatus is provided which automatically comes into action, so that after the engine has used the sand in the fore or reverse direction, the rails are cleaned with hot water to prevent interference with the track circuits.
The tender is of the 6-wheeled type of 15ft. wheel base, With a capacity of 9 tons of coal and 4,000 gallons of water. The coal bunker has been carefully arranged so that as far as possible the coal will be self-trimming. A bunker door gives access to the coal space from the footplate and there is ample toolbox space on the front of the tenders.
The necessary firing irons are housed in a suitable cavity on the left-hand side of the tender.
The water pick-up and tender hand brake handles are arranged vertically. Bevel wheels are provided for transferring the motion to their respective gears.
A steam brake is provided on each of the six tender wheels and is applied simultaneously with the steam brake on the engine.
As a further means of obtaining a smooth-riding locomotive, the intermediate drawgear has been carefully designed with buffing spindles controlled by coiled springs.
The buffing spindles have a specially designed head which rides on inclined planes, provided on the hind engine buffer beam.
The total wheel base of the engine and tender is 53 ft. 2¾ ins. and the total length over the buffers 63 ft. 7¾ ins.
Site contents Copyright © LMS Society, 2025
December 1st, 2025
Site contents Copyright © LMS Society, 2025