Class 201/202/203 (Hastings DEMUs)

The Class 201 (also known by its SR Alpha code as 6S) diesel-electric multiple units were built for the modernisation of the London to Hastings route allowing the replacement of steam. Narrow tunnels and the resulting reduced clearance meant the line was not electrified like much of the rest of the Southern Region and special units with a narrower body were needed [1] - being 2.74m wide, a contemporary "normal" DMU like the Class 101 was 2.82m wide.

The Class 201s were similar in style and in many ways technically to the large Southern fleet of EMUs but power to the traction motors was provided from the 2 diesels instead of from a third rail! Unlike the DMU fleet elsewhere the Class 201 and other early Southern Region DEMUs has a single large engine mounted above the floor per power car instead of smaller motors mounted below, and electric instead of mechanical (or hydraulic) transmission [2].

Number built: (201/6S) 42 cars (in 7 6-car sets)
(202/6L) 54 cars (in 9 6-car sets)
(203/6B) 42 cars (in 7 6-car sets)
Built: 1957
Builder: BR Eastleigh
Engine: English Electric 4SRKT diesel per DMBS
Power: 1, 000 hp (746 kW)
Formation: (201-202) Driving Motor Brake Standard (DMBS)+Trailer Standard (TS)+
Trailer Composite (TC)+TS+TS+DMBS
(203) DMBS+TS+TC+Trailer Restaurant Buffet (TRB)+TS+DMBS

The 7 6-car Class 201 sets were later supplemented by the similar Class 202 (6L) and 203 (6B) which used full-length carriages (the 201s were shorter than normal coaching stock) and the 203 included a buffet [3] though these were later withdrawn reducing the 203s to 5 car sets [4]. The units made the Hastings route their own for the next 30 years and could also be found on other Southern routes. Some 201 units were disbanded in the 1960s to form part of the Class 206 "Tadpole" DEMUs which unusually mixed the narrow profile Hastings units with normal profile stock from elsewhere [5].

The Hastings route was finally electrified in 1986 and most of the 201/2/3 fleet was withdrawn though a small number remained in service on other routes in the early 1990s. One complete set of the Class 201 has been preserved and is mainline certified. A number of other cars have also been preserved. One of the buffet cars from the Class 203 was rebuilt in the late 1960s to help develop tilting and active suspension technology for the APT and known as QXA RDB975386 Laboratory 4 [6].
Preserved set 1001 at Leamington Spa

Preserved set 1001 at Leamington Spa

Former 203 buffet now Laboratory 4 preserved at the Electric Railway Museum
[1] Colin J. Marsden (ed.), Modern Locomotives Illustrated No. 218 April-May 2016 (Southern Region DEMUs and Class 210) p. 4
[2] Brian Haresnape, Diesel Multiple Units: The Second Generation and DEMUs (Ian Allan, 1986) p. 6
[3] Colin J. Marsden, DMU and EMU Recognition Guide (Ian Allan, 2013) p. 96
[4] Gavin Morrison, British Railway DMUs in Colour (Ian Allan, 2010) p. 21
[5] Haresnape p. 26
[6] Colin J. Marsden, Departmental Stock (Ian Allan, 1984) p. 30