Sutton's Locomotive Workshop British Railways Sulzer Type 2 Operating Manual - page 12
placed above the power unit. Dependent on period/livery, the models either display
the original resonator silencer with its raised, curved surface and circular exhaust
port, or a later plated-over roof section and simplified direct outlet.
Frame fairings
Aesthetics, it could be argued, was not of high importance with these Derby Type 2s.
However, one concession was the contoured fairings that enclosed the longitudinal
frames and their associated pipe and cable runs at solebar level. Hinged in sections,
to give access for maintenance, they were subject to regular damage and became a
hindrance. They were removed at half-life overhaul, leaving the frames with a very
utilitarian appearance. The fairings were dropped completely from the later Class 25s.
Underslung fuel and water tanks
Weight limitations and operational requirements led to several arrangements of
underslung fuel and boiler water tank. The diesel fuel tank, at the No. 1 end, was
reduced in capacity (and physical height) from 630/546 to 520/500 gallons whilst the
water tank was reduced in capacity (and length) from 600 to 450 gallons both from
D5050. In addition, sight glasses were quickly superseded by circular gauges. On the
freight only locomotives employed on Tyne Dock-Consett iron on workings, and in
later years when boilers were isolated, the water tanks were removed completely.
Bogie cab footsteps and sandboxes
Both two and three-rung bogie footsteps exist. The former (original) design was
restricted to pilot scheme and early production locomotives before the arrangement
was changed due to experience (the steps were too widely spaced to making climbing
awkward). A revised shape of sandbox, to simplify fabrication, was also introduced
with the later Class 25. Component swaps and repairs quickly led to the mixing of
these designs to the extent that some locos sported different sandboxes at each end!
Bodyside footsteps and battery isolating switch cover
As a direct result of spreading overhead electrification, the bodyside footsteps/hand
holds were plated over to prevent access to the roof. At the same time a small cover
was placed over the coolant overflow outlet adjacent to the roof scavenger fan. The
exterior battery isolating switch cover was found to work open due to vibration and
so was secured by a more foolproof locking bar. All these in-service modifications
are included where necessary, most commonly on blue-liveried locos.
Boiler pressure relief valves and roof water filler cover
Several arrangements of steam pressure relief valves exist (linked to equipment
routing and different workshops) in segments cut out of the roof, above the boiler
compartment. Our models allow for these variations to be represented. The hinged
cover for the roof-mounted boiler water filler point is also included as a separate
etched item. This component was quickly dispensed with in service due to its fragility.
High-level air pipes
In 1964, the Tyne Dock-Consett iron ore trains were taken over by Type 2s working
in multiple, replacing steam traction. NER-based locomotives D5102-11 were
allocated to this role having been modified with an air compressor and control
equipment in place of the boiler. The water tanks and steam heat piping was removed
and new high-level air pipes installed on the front ends in order to provide a supply
for the compressed air-operated hopper doors on the wagons. The distinctive pipes
remained in situ when the locos were transferred away after the traffic ceased. If you
wish to model these locos, contact us for a special upgrade pack, containing revised
underbody details and a pair of high-level pipes.
Removal of front end doors
As was convention at the time, these locomotives were built with front end gangways
intended for crew access when running in multiple. It was found to be a little used
feature and the doors were soon locked out of use. As a constant source of drafts and
water ingress, they were first covered by strips on some Scottish-based machines
before a prolonged Works programme of removal and re-sheeting took place. Derby
and Glasgow Works had differing techniques, the latter choosing to reposition the
middle marker lights and discs on the centre-line. Not all locos were treated before
withdrawal, many retaining the front end doors.
Headcode boxes and headlights
It was not until well through the build that a redesign of the front end took place with
the adoption of train reporting number apparatus (headcode box) on the cab roof.
The simplified front end, albeit still with doors, was now devoid of headcode discs
and marker lights leaving just two low level tail lights. This change took effect from
D5114 onwards. A batch of these locomotives was allocated to Scotland and was
subsequently fitted with a pair of headlights on the central nose section at each end.
SLW Class 24 Operating Manual
Page 23
Page 22
SLW Class 24 Operating Manual