The Clayton Steam Railcars

Clayton Diagram 92 Railcar No. 42 Chevy Chase at Doncaster Works in 1928

Clayton Wagons Ltd of Lincoln started to build steam railcars in 1927. The LNER purchased a total of eleven between 1927 and 1928. Although similar in concept to the contemporary Sentinel steam railcars, there were a number of differences. The most visible difference was the separate coal bunker and water tank that was carried on the power bogie in-front of the coach body. The engine units had two cylinders with piston valves, and drive was provided via a spur gear on the driving axle. The axles on the power bogie were connected with a coupling rod, although these were often removed at a later date due to reports of vibration.

The initial trial car was delivered in July 1927. Numbered No. 41, this only received the name Pilot in 1929 when it was renumbered as No. 2121. Described by Diagram 91, this had a saloon that was very similar to the Sentinel railcar saloons. A gangway was positioned off-centre to the left, with three seats on the right and two on the left. A luggage compartment was located at the rear. Exterior passenger doors were sliding, but the driver doors at both ends were hinged.

Trial No. 41 was followed by the production series of ten railcars built between May and July 1928. The first nine were to Diagram 92. These had a body that was one foot longer, and the seating capacity was increased from 60 to 64 passengers. The luggage compartment was moved from the front to the rear, and shorted from 6ft to 5ft 4in in length. The 3+1 seating arrangement was retained, but the gangway was moved to the right side instead of the left.

The final railcar (No. 2130 Bang Up) was built to Diagram 94. Externally this looked the same as the Diagram 92 railcars, but featured a central gangway with 2+2 seating that reduced the capacity to 44 seated passengers.

The Clayton railcars were fitted with a vertical boiler with an outer cylindrical shell and an inner firebox. The middle portion of the firebox was pressed into a square cross-section. The boiler contained 72 water tubes. 24 tubes had screwed ends and were considered to be stay tubes that supported the flat surfaces of the firebox.

Clayton Wagons Ltd entered liquidation in October 1929, and the LNER found it increasingly difficult or expensive to source replacement parts. The LNER eventually had to manufacture many of the required parts in its own shops. Crankshafts were particularly prone to breakage, and the boilers gave a variety of problems.

The Clayton railcars were notorious for their production of sparks. In March 1930, orders were given to replace their original spark arrestors with baffle rings of the type fitted to the Sentinel railcars. This was moderately successful with only a small reduction in steaming ability. Unfortunately the rings also led to hot cinders making their way into the engine compartment through a hole in the roof around the safety valve exhaust. This was successfully sealed with a plate. Reports suggest that damage cause by sparks produced by a Clayton railcar resulted in the LNER losing a court case in early 1932. The Drawing Office in Doncaster was asked to investigate spark arrester alternatives that would not be too visible to the public. New solutions were not forthcoming and the problem appears to have been solved in 1935 when a fine 0.25in wire mesh arrester was found to work with no interference to steaming. This became standard in September 1935.

As the Clayton works were in Lincoln, running-in trials were performed between Lincoln and Woodhall Junction. No. 41 was allocated to the North East (NE) area in order to allow comparisons with early Sentinel railcars. No.41 was initially allocated to the York-Whitby-Scarborough-York circuit. It was joined by six of the production railcars, and all were allocated to Heaton where they operated services to Leamside, Morpeth, North Wylam, Prudhoe, and Blackhill. Comet was transferred to Norwich in 1934. Poor reliability was cited in a 1935 report that recommended that all of the remaining Heaton railcars were withdrawn.

The remaining four Clayton railcars were delivered to Lincoln (Chevy Chase), Doncaster (Railway & Bang Up), and Lowestoft (Transit). Bang Up was moved to Hitchin on 19th August 1928 to operate services over the Hitchin to Hertford North line. Bang Up was then transferred to Lowestoft in May 1930, and Sentinel railcar Waterloo took over the Hitchin service. Railway was also transferred from Doncaster in 1928, this time to Immingham. By 1929 it was allocated to Annesley for ten months to operate the 'Dido' workers train. After this duty, it joined the other three Clayton cars in the Norwich district. Typical duties for the Clayton railcars were on local short-mileage branch line runs.

Rapid was the first withdrawal in July 1932. With increasing maintenance problems, and a shortage of less strenuous short mileage work, the remainder were withdrawn between April 1936 and February 1937. Due to their short lives and persistent problems, none of the Clayton railcars clocked up significant mileages. Final mileages ranged from 72,774 (Rapid) to 174,691 (Chevy Chase).

Clayton Trailer Cars

Clayton railcar trailer No. 2166 at Selby

The LNER also purchased eight 4-wheel trailers from Clayton for use with these railcars. These had a 26ft wheelbase and a body length of 40ft 9in. Standard passenger capacity was quoted at forty with room for twelve standing. A large luggage compartment was designed for 1 ton of luggage, but it could alternatively seat sixteen additional passengers on tip-up seats. Both compartments had sliding doors, and they were also connected with a communicating door. Connections were provided for vacuum brake, electric light, and steam heating.

Most were withdrawn and condemned by British Railways in 1949, although No. 31071 was withdrawn in 1948 and lay derelict at Seafield until it was sold for scrap in 1968. At least one was seen in BR Departmental use after withdrawal. Many of the trailers shared a common fate of being turned into summer houses.

Technical Details

In common with the Sentinel railcars, the LNER kept poor records of the superheater dimensions. The weights were also reported in an inconsistent manner. Diagram 91 weight 28 tons 7cwt 3qtrs (with coal and water), whilst Diagram 92 and 94 weight 28 tons and 28 tones 10cwt respectively (empty). Seats also differed between diagrams. Diagram 91 (No. 41) had 0 seats, and Diagram 94 (No. 2130) had only 44 seats.

Cylinders: (x2) 6.75x10in.
Valves: piston
Transmission: gear
Boiler: Diameter (top): 3ft
Pressure: 275psi
Heating Surface: Total evap.: 70.95 sq.ft.
Firebox: 23.75 sq.ft.
Superheater: Not recorded
Tubes: 47.20 sq.ft. (72x 1.5in)
Grate Area: 4.12 sq.ft.
Wheels: Front bogie: 3ft 6in
Rear bogie: 3ft
Wheelbase: Front bogie: 7ft
Rear bogie: 7ft
Total: 49ft 6in
Length: Over Body: 51ft
Over Buffers: 59ft 7.25in
Seats: 64


The last Clayton steam railcar was withdrawn in February 1937, and none survived into preservation.


Garth Patrick of GP Models sells kits of the Clayton railcar and trailer for O gauge (7mm scale).

Railcar Names

Some railcars were renumbered on one or two occasions, and these are listed with the date of the renumbering.

Diagram No.Build DateLNER No.2nd No.3rd No.Disposal DateName
917/27 412121 (3/29)9/36Pilot
925/28 2857/32Rapid
925/28 2879/36Royal Sailor
926/28 2899/36Wellington
927/28 2969/36Wonder
926/282120 42 (3/29)43302 (1/34)2/37Chevy Chase
926/28212161999 (3/28)43305 (8/34)2/37Transit
926/282122 43 (3/29)43303 (6/35)2/37Railway
947/282130 44 (3/29)43304 (8/34)1/37Bang Up