Mon 26 Feb 2018 01:29:22


British Railway History Item


Class 10100 BR/Fell Experimental Locomotive

British Railways and L.F.R. Fell Experimental Locomotive.

Introduced in January 1951, locomotive No. 10100 was a revolutionary machine. It was a joint production of Fell Developments Ltd. using patents taken out by Lieut.Col. Fell and the London Midland Region of British Railways. The locomotive was built by a collection of contractors, including British Railways, the Ricardo Company and L.F.R. Fell.

There are four Davey Paxman 500 b.h.p. diesel engines, located in pairs under the two casings at the outer end of the Iocomotive, and two auxiliary 150 b.h.p engines for driving the super-charger blowers radiator fans vacuum exhausters, water circulating pumps, and other auxiliaries. Each main engine drives the input side of a fluid coupling the output side of which passes into the four top corners of the gearbox driving through bevel gears on to transverse shafts into each of which is mounted a primary differential.

The gearing arrangements are rather too complex to describe in detail, but the general principle is that if the locomotive be started on one engine the primary and secondary differentials produce a gear ratio of 4 to 1, providing the same effort at the driving wheel rims as if all four engines were working, but at one quarter of the locomotive speed. So the engines are cut in one by one, the first engine being used up to 6 m.p h. the second from 6 to 17, the third from 17 to 24 and the fourth for all speeds from 24 to the rated maximum of 78 m.p.h.

The locomotive is of the 4-8-4 type, and so differs completely from the normal, early 1950s high-powered diesel-electric locomotive carried on bogies of which the axles are motor-driven. In No. 10100, the drive is through tubular quill shafts to the two centre axles, which are connected by ordinary coupling rods to the outer coupled axles.

There are fully equipped driving positions at both ends of the centre cab, which houses the gearbox, the auxiliary diesel engines and also two automatically fired boilers for supplying steam heat to trains.

A unique feature, for a diesel locomotive of the period, is the provision of a small water-scoop to enable the 500-gallon water tank supplying these boilers to be replenished as required from track troughs.

The loco was used on many lines on the London Midland Region of BR, until withdrawn from service in November 1958. It was cut up for scrap at Derby Works during January 1960.

The leading dimensions of No. 10100 are as follows:

BUILT: 1951 by the British Railways Derby Locomotive Works.

ENGINE: 4 Paxman 12 Cylinder Engines developing 500hp each.


CYLINDER: dia. and stroke: 7 in x 7 3/4 in.




MAX SPEED: 84mph.


WEIGHT: in working order 120 tons.

WHEEL ARRANGEMENT: 4-8-4 using 4-(4-4)-4.

DRIVING WHEEL: diameter 4 ft. 3 in.

LENGTH: over buffers: 50 ft. 10 in.


FLEET STRENGTH: NIL (Loco Withdrawn 1958)

Last Updated : Monday 21st October 2002 23:10

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