Introduction
At the commencement of the British Railways’ modernisation plan in 1955,
the largest type of main-line diesel electric locomotive included in the programme
was that designated Type 4, with an engine continuous rating of at least 2000
hp. At that time there was some uncertainty whether a 6-axle locomotive could
be built having a 19 ton axle-load specified to give the required route availability.
As there was also in existence a suitable bogie design for a 1-Co-Co-1 wheel
arrangement, this type of locomotive was chosen.
Since that date, considerable experience had been gained in the light-weight
methods of construction and improved manufacturing techniques had been developed,
so that it had now become quite practicable to design a Type 4 locomotive with
a Co-Co wheel arrangement to meet the 19 ton axle-load limit. At the same time
it had been possible to comply with the newly specified engine power requirement
of at least 2500 hp for traction plus some 250 hp for electric train heating
purposes, without resort to high-speed engines.
In view of these developments, a consortium was formed, consisting of Associated
Electrical Industries Limited (AEI) ; Birmingham Railway Carriage & Wagon
Company Limited (BRC&W); and Sulzer Brothers (London) Limited (Sulzer),
to design and build, as a private venture, a prototype locomotive to meet British
Railways’ latest Type 4 requirements. The 2750 hp diesel-electric locomotive
named “Lion” was the result of this exercise.
Many new and interesting features were embodied in the design, of which the
following are the more outstanding (Full are given in detail in the “Specification”
link on the menu):
Provision had been made for the supply of both steam and electric train heating
without exceeding the specified maximum axle-load.
Extensive use was made of rubber in the suspension system, the bogies having
rubber cons pivots of the Alsthom type while the axleboxes were supported by
rubber-bushed radius arms, with the aim of securing good riding qualities at
all speeds, and reducing wearing surfaces to a minimum. The mechanical structure
was of light-weight design, using steel for all stressed parts, while the doors,
roof-traps, et cetera, fibreglass was adopted.
The whole structure was completely tested with strain gauges under static conditions
with an applied end-load of 200 tons.
A translucent fibreglass roof-trap fitted above the engine could be pneumatically
raised to allow hot air to escape and so improve conditions for maintenance
work on the engine after it had been running
The auxiliary equipment, wherever possible, was in the form of self-contained
sub-assemblies, to facilitate removal for overhaul.
The radiators and air filters were roof-mounted, the latter being easily changed
from outside the locomotive.
The most advanced techniques were applied to the design of the generators and
traction motors, which were insulated throughout to British Standard Class H
The engine, which although of the same basic design as those already in service
in a large number of Type 4 locomotives, had been up-rated to 2750 hp mainly
by the introduction of intercoolers and by small increases in b.m.e.p. and speed.
[Continue to Specification]
