British Rail Class 35

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BR Class 35
TOPS numbers Not Carried
Early numbers D7000–D7100
Builder Beyer Peacock (Hymec) Ltd
Introduced 1961
Wheel Arrangement B-B
Weight 75 t 8 cwt
Height 12 ft 10in
Width 8 ft 10 in
Length 51 ft 8.5 in
Wheel Dia. 3 ft 9 in
Total Wheel Base 36 ft
Minimum radius N.A.
Maximum speed 90 mph
Engine output 1,700 hp at 1,500 rpm
Max. Tractive Effort 46,600 lbf
Power at Rail N.A.
Brake type Air locomotive brake
Vacuum train brakes
Brake force 57 tons
Route availability 6
Fuel Tank 800 imperial gal
Heating type Steam
Preserved D7017 at Minehead in 1979
Enlarge
Preserved D7017 at Minehead in 1979

The British Rail Class 35 is a class of mixed traffic Bo-Bo diesel locomotive with hydraulic transmission. On account of their Mekydro-design hydraulic transmission units, the design became known as the Hymeks.

Contents

[edit] Development

The type was developed for the Western Region of British Railways, which had opted for lightweight locomotives with hydraulic transmission when allocated funds under the British Railways Modernisation Plan of 1955. 101 of the class were built between 1961 and 1964 when it became apparent that there was a requirement for a medium power diesel-hydraulic design for both secondary passenger work and freight duties.

The builder, Beyer Peacock (Hymek) Ltd, was a joint venture between Bristol Siddeley Engines (BSE) (licensed to build Maybach engines), Stone-Platt Industries (licensed to build Mekydro transmissions) and the locomotive manufacturer Beyer Peacock. At the time they were built, the Hymeks were the most powerful diesel hydraulic locomotive operating with a single engine - the Maybach MD870. Unlike the higher-powered diesel-hydraulic Warship and Western locomotives in the Western Region fleet (with dual Maybach MD655 engines), the Hymeks were not based on an existing West German design.

Withdrawal from service began in 1971, and by 1975 all had been withdrawn. Their early withdrawal was caused, primarily, by issues within BR concerning the non-standard hydraulic transmission. They were allocated to Bristol Bath Road, Cardiff Canton and Old Oak Common.

[edit] Liveries

When first built, the Hymeks were given a more elaborate livery than many of the contemporary British Railways diesel classes. The main body of the locomotive was the standard dark Brunswick green, but with a lime green stripe along the bottom of the bodywork. The roof was medium grey, and the finishing touch was to paint the window surrounds in ivory white. In the early 1960s, yellow warning panels were added to the lower part of the front ends, in accordance with BR's then-new policy. Following the corporate identity campaign and the change of name to British Rail plus introduction of the "double arrow" logo in 1964, some locomotives received all-over British Rail blue with small yellow warning panels. This was quickly changed by the return of off-white window surrounds. The final variation was BR blue with full yellow ends, the yellow being extended around the cab side windows.

[edit] Operational service

The type was initially employed on secondary passenger services, such as Paddington to Hereford and semi-fast services to the west of England and Wales. They also worked pickup freights throughout the Western Region as a mixed-traffic design. The Hymeks were capable of operating in multiple, but only with each other. The electro-pneumatic control system allowed only one trailing locomotive to be controlled (by one driver): some trains were operated by three locomotives (all at the front of the train), but in these cases only two locomotives were connected in multiple, the third having a separate driver. None of the class was named.

[edit] Withdrawal

Prejudice against the Western Region's diesel-hydraulic fleet had been present in other divisions of British Rail ever since the designs were first ordered. The aim of the Modernisation Plan, and in particular the rapid conversion of the entire BR fleet to diesel and electric traction, had been to stem BR's financial losses thought to arise partially from the labour-intensive nature of steam locomotive use. Although steam was eliminated from mainline use by 1968, many unsuitable designs of diesel locomotive had been rushed into service in the rush to achieve steam-free operation. The National Traction Plan of 1967/8 decreed that designs proving unreliable, expensive to maintain or non-standard should be eliminated as quickly as possible in order to reduce the number of diesel classes from 28 to 15 by the year 1974. The engineering factions of the British Railways Board, the body that oversaw BR's operations from 1962 onwards, felt that all of the Western Region's diesel-hydraulic fleet should be counted as non-standard and should be withdrawn as quickly as possible. Despite the fact that the Hymeks were statistically the most efficient of the Western Region's diesel-hydraulic fleet in terms of reliability, the entire class was withdrawn between 1971 and 1975. They were replaced by class 37 diesel-electric locomotives made redundant in other regions as a result of line closures and general decline in rail-borne freight traffic throughout the 1960s.

[edit] Preservation

Four locomotives survived to be preserved.

D7076 survived, along with sister locomotive D7096, at the Railway Technical Centre near Derby, where they were used as dead loads for research purposes. Warship no. D832 Onslaught was additionally present at this site. Both Hymeks were in poor condition, however it proved possible to rebuild one by using the other as a donor locomotive. D7076 was therefore restored using parts from D7096 and carries the number D7096 internally in one driving cab as a nod to the donor locomotive, which was reduced to a shell and subsequently scrapped. As of May 2006, D7076 is the only preserved Hymek in operational condition.

[edit] Hymeks in fiction

A Class 35 Hymek was featured in The Railway Series books by Rev. W. Awdry (the original 'Thomas the Tank Engine' stories). D7101 (a fictional number), later named Bear on account of the growling noise made by his engine, was introduced in book No.23 Enterprising Engines as one of the few good diesels. He however was not made into a model or featured in the Thomas the Tank Engine and Friends TV Series.


[edit] References

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