Five two car sets were ordered from British United Traction for the Birmingham (Part 2) scheme, and 15 sets for the Manchester Part 1 Scheme (Buxton area) by the British Transport Commission in August 1955. BUT started work on the vehicles at the Crossley works in Stockport, but when this closed, they were started afresh at the Park Royal factory in Abbey Road, London. They were allocated Park Royal body numbers B38830-49 for the power cars and B33850-69 for the trailers. Many of the works drawings for the bogies and under frame are on Crossley Motors drawings. The cabs had been designed to have an upper marker light, similar to those fitted to the class 104's, but this was deleted in early 1957.
Design and construction (From the Railcar website courtesy of Stuart Mackay)
design was being considered, it was established that the use of orthodox body
& underframe construction would produce an un-favourable power-weight
ratio, bearing in mind the nature of the intended operation of the cars and the
resultant need for good acceleration. So, to achieve the required strength of
structure with the necessary weight reduction, an integral steel design was
based on a frame, not self-supporting. Two 8in x 3in channel section
longitudinals of standard rolled section threaded through folded channel
transverse members (a patented feature) which tapered up to the 5/16in m.s.
fabricated two section solebars. When the body sides were erected, an
additional 5/16in thick m.s. angle was welded the full length of the solebar
bringing it up to a depth of 15in with interval stiffening beneath each doorway
opening. Drawgear and buffing loads were distributed throughout each end of the
frame by diagonal members and plating, taking the main component of these loads
to the bolster, a fabricated assembly based on two boxed transverse members.
The complete frame was welded in one jig following setting up and incorporation
of the required camber.
(The design seems to be based on the Railcars built in the early 1950's for export to Ireland and Argentina - shown in plate 5 of the export brochure here)
bodyside structure used 14g m.s. top hat section pillars welded on the inner
face to the angle solebar extrusion members, and these, together with "top
hat" and Z-section longitudinal members were jig welded in units before
panelling. To minimise distortion, the exterior 16 s.w.g. exterior panelling
was welded into bodyside units, clamped to the bodyside framing units in a
welding fixture and welded to the pillars through vertical slots in the pillar
achieve the necessary distribution of stress concentrations in the body side
and underframe shown up in the stress diagram, a deep cantrail was essential
and was achieved by the use of a 15 inch deep 10 s.w.g. exterior core panel in
one piece running the full length of the body. The roofsticks were two
aluminium alloy angles spaced by 1/8 inch alloy connecting plates (Said to have been based on techniques developed by PRV in the construction of Halifax bombers in the Second World War) They were
connected to gussets welded to the Z section longitudinal member at the top of
the roof stress panels. The roof panels were 16 s.w.g. aluminium alloy, riveted
to the roof sticks and overlapped and riveted to the stress panels. The
exterior cove panel, combined with the double angle roof sticks and a
connecting channel lower cant to pick up the pillars, resulted in a structure
of great stiffness, particularly in the longitudinal stress concentrations.
static load testing a maximum deflection on the frame line of 1/8in was
recorded with 200% overload, with consistent return to zero on overloading. The
main body sides were welded to the set up underframe and the solebar extrusion
angle, which formed the body side bottom member, was welded the full length of
the solebar. The front and end frames, also jig built units, were then mounted
and the complete roof, again a jig built unit, was secured at cant level. Until
this stage the underframe remained supported throughout its length with the
necessary camber, and only when the complete shell was assembled was the unit
alloy Oleo pneumatic buffers and standard screw couplings were used. Two of the
channel section cross-members were positioned at the bogie pivot positions,
spaced by 5/16 in m.s. plate welded above and below. The bogie design followed
the BR standard steel design for railcars, except using folded steel sections
on place of rolled members. Standard BR pattern 3ft diameter wheels and axles
were used with SKF self-aligning roller bearing axleboxes, and standard pattern
BR brake blocks and carriers. The underframe and bogie frames were supplied by
John Thompson (Motor Pressings) Ltd, with wheels and axles from Owen &
Dyson Ltd. Laminated springs were by Willford & Co Ltd and coil springs by
Turton Bros & Matthews Ltd.
equipment was powered by an engine driven Stones generator and control panel.
On the trailer car the generator was bogie mounted and axle driven, and
incorporated a reversible drive. Batteries (BR type BR A 2) were lead acid of
440 Amps/Hour. Saloon lighting could be either switched to full or half, and
was controlled from either cab or the guards compartment. The main wiring for
the lighting, control and heater control circuits was carried in trunking at
floor level. The standard DMU heating system of two Smiths combustion heaters
was used, ducted to outlets throughout the saloons.
was originally by two 22 inch vacuum cylinders in the power car (later changed
to the new standard 21" rolling ring type) and two 18 inch cylinders in
the trailers. The cylinders were controlled by the Gresham & Craven quick
release brake system. Rotary exhausters were driven of each engine via v-belts
connected to the gearbox input shaft. Two engine mounted Westinghouse
compressors supplied the air for engine, gearbox and final drive control units,
as well as the horn.
Interior (From the Railcar website courtesy of Stuart Mackay)
blue asbestos supplied by J. W. Robertson Limited was sprayed on the inside of
all exterior panelling. The flooring, which was bolted to the main crossmembers
and to the intermediate supports, was 7/8 inch thick Douglas fir ply, with 1/2
inch thick insulation on top.
The second class seating was "bus"
type tubular frame seats, with a polished top handrail, in 2 + 3 formation.
These lower back seats were promoted as giving better visibility and an aid to
reducing travel sickness. All seats had Dunlopillo cushions and Hairlock
squabs. The first class, also formed from tubular framing, were higher backed,
with armrests in a 2 + 2 style. The original moquette used was blue and grey in
first and maroon and grey in second
interior walls were unusual in that they were leathercloth covered lining
panels up to cantrail level, in colours matching the seats. Ceiling panels were
Laconite. Rubber filled aluminium mouldings were fitted to protect the enamel
of the roof covering behind the anodised aluminium tubular luggage racks. These
were supplied by Deans & Son (Yorkshire) Ltd who also supplied the seat
frames. There were flush-fitting coir fibre door mats in a sunken pan at each
door way. The floors had 3/16 inch thick linoleum, covered with carpets in
vestibules were formed by glazed partitions trimmed to match the saloon, and
first class was separated by a sliding door.
full-drop balanced windows were fitted to exterior doors, and the main side
windows were glazed in a wide aluminium pan which formed the drain trough,
supplied by Hallam, Sleigh & Cheston Ltd. Standard sliding window
ventilators were fitted, with Airvac extraction ventilators in the roof. The
toilets were finished in ivory enamel with black mouldings.
drivers desk, with orthodox control layout, was faced with black formica.
The original fabric used on the second class seats was this colourful wine moquette!
The Western Region sets
In May 1970 two sets (50413/56169 & 50413/56168) were dispatched to Cardiff to release two class 121 units. The trailers were stored and the DMBS' coupled to form 'power twin' set CTN100 for the Cymmer and Bridgend services. The experiment does not seem to have been a success as all four vehicles were sent to Reading on June 7th forming sets RDG113 & RDG114 respectively. Here they worked the Henley, Windsor, Borne End/Marlow, Greenford and, on Sundays, Paddington services. In October they were joined by 50411/56167 & 50412/56166 (becoming sets RDG 111 & 112) These latter four vehicles remained at Reading until withdrawl in May 1972, but the former Cardiff units were transferred to Plymouth Laira in January 1972 and used on the Cornish branch lines including Kingswear. Here they were joined by withdrawn 50412 - presumably as a source of spares. In December 1972 the two Laira sets were withdrawn and purchased by the West Somerset Railway. They were stored at Laira, Bristol Marsh Junction and finally Taunton, before arriving at Minehead in April 1976. 50413/56168 were offered for sale by the WSR in March 1991 but as there were no takers the vehicles were scrapped in May of that year. 50413 and 56169 remained on the WSR until being sold to the Helston Diesel Group in April 2006 where they are undergoing restoration.
56169 in West Somerset Railway Livery
When new the bodies were painted in the lighter Brunswick green livery, with a light grey roof and red buffer beams. under frames were black and exhaust silencers green. Cream lining was painted above and below the Windows. During the 1960's the sets were repainted in the darker multiple unit green and dark grey roofs. Feather plumes (Speed Whiskers) were added to the cab fronts before being replaced by small yellow warning panels. In the late 1960's with the exception of 50411/12 the class received the new Rail Blue livery, initially with the small yellow warning panels (and BR double arrow on the cab doors) but eventually full yellow cab fronts and the arrow relocated under the first window. The first class section on the DTC(L)'s was marked with a yellow band above the windows in all liveries.
50396 and 56162 received the research departments red and blue livery when they became Lab 5 and its trim.
50397 was painted yellow for its use as a viaduct inspection unit
56156 had its gangway end painted yellow when it was converted to a sandite unit
50396 and 56162 in research livery at Edinburgh Waverly on 4/3/86
Five class 103's joined the Departmental fleet
50396 & 56162 became ADB975089 & ADB975090 'Laboratory Coach No5'
50397 & 56160 became DB975137 & DB975228 'Universal Viaduct Inspection unit no 1'
56156 became Sandite unit ADB977047 and its gangway was removed.
50406 was written off due to fire damage
50410 suffered fire and collision damage and was withdrawn
50407 & 56154 were badly damaged in the Chester oil train crash and scrapped
56153 was withdrawn after hitting a tree on the Conwy valley line, badly damaging the cab.
56160 suffered collision damage to the drivers side of the cab