Class 317 [Updated]

The Class 317 EMU is another class of multiple unit based on the Mark 3 coach design similar to the Classes 150 and 455 among others. Built in the early 1980s they are hard working veterans still carrying thousands of passengers daily into London. The 317 was the first British Rail multiple unit designed for driver only operation though this did result in a delay in their introduction into service because of a dispute with the unions [1][2]. All of the 317's service life to date has been on suburban services to London from the likes of Bedford, Luton and Cambridge though for a time in the late 1980s they did venture as far afield as Birmingham.

Number built: 288 (72 4-car sets)
Built: 1981-82, 1985-86
Builder: BREL York
Engine: 4 GEC G315BZ traction motors (25kV AC OLHE)
Power: 1, 328 hp (990 kW)
Formation: Driving Trailer Standard Open (DTSO)+Motor Standard Open (MSO)+
Trailer Composite Open (TCO)+DTSO

The Class 317 was built in two batches, the first batch 317/1 was built for St Pancras to Bedford services. A second batch 317/2 was built a little later for services out of Kings Cross. In the late 1990s some units were refurbished and upgraded, including fitting a new pantograph, as the 317/6. In the mid-2000s some 317s were refurbished as 317/7 for the Stansted Express, 317/5 for Greater Anglia services while others were refurbished and updated as 317/8.

Despite a long life already the 317 could remain in service for another 20 years with plans for a major rebuild and refurbishment and the fitting of new traction motors and equipment however if this life extension does take place it will be on different rails to where they are at present. They are due to be replaced by new Electrostar and Aventra EMUs from current routes over the next couple of years.

317 652 at Cambridge Heath

317 667 at Liverpool Street

Another view of 317 652 at Cambridge Heath
[1] Alec Swain, Overhead Line Electric Multiple-Units (Ian Allan, 1990) p. 71
[2] John Glover, BR Diary 1978-1985 (Ian Allan, 1985) p. 81

Class 310

The Class 310 was built for high-density semi-fast services along the West Coast Main Line from London to Northampton and Birmingham [1]. The 310s were the first EMUs based on the Mark 2 coach had a lot of effort put into them by British Rail, the exterior design was thanks to the Design Panel and used curved glass on the windscreens (later a maintenance nightmare and was replaced by flat glass), a lot of work was put into the quality of the ride and the 310s were the first series built multiple units to have disc brakes [2].

Number built: 200 (50 4-car sets)
Built: 1965-67
Builder: BR Derby
Engine: 4 EE546A traction motors (25kV AC OHLE)
Power: 1, 080 hp (810 kW)
Formation: (310/0) Battery Driving Trailer Standard Open Lavatory (BDTSOL)+
Motor Brake Standard Open (MBSO)+Trailer Standard Open (TSO)+
Driving Trailer Composite Open Lavatory) DTCOL

All 310s were originally 4-car sets, later a number was reduced to 3 car sets (310/1) for use on local services around Birmingham. The 310/0s later worked on the London, Tilbury and Southend line after being replaced on the WCML. In the post-privatisation era they were operated by LTS Rail and Central Trains but all were withdrawn by 2002. Unfortunately none have been preserved.
Regional Railways 310 109 at Barking (Photographer unknown)

[1] Colin J Marsden, DMU and EMU Recognition Guide (Ian Allan, 2013) p. 230
[2] Alec Swain, Overhead Line Electric Multiple Units (Ian Allan, 1990) p. 52

Class 316 and 457

To help develop the Class 465 "Networker" multiple-unit BR took 4 coaches from the Class 210 DEMU and used them as a test bed, firstly as the Class 457 for DC third rail and later as the Class 316 for AC overhead [1]. The former Class 210s were converted at RTC Derby and then ran for a while on Southern Region. The 457s were fitted with three-phase traction motors which allowed for significant energy savings over earlier types of motor [2].

Number built: 4 (1 4-car set)
Built: 1989-90 (Class 210s originally built 1981)
Builder: BREL Derby
Engine: Brush three-phase traction motors (750v DC third rail (457) 25kV AC OHLE (316))
Power: 1, 140 hp (850 kW) 
Formation: (457) Driving Motor Standard Open (DMSO)+Trailer Standard Open (TSO)+TSO+DMSO
(316) DMSO+Pantograph Trailer Standard Open (PTSO)+TSO+DMSO

Later they returned to Derby and were converted to AC traction by inserting a PTSO from a Class 313 and worked AC electrified lines North of the Thames. Of the 4 cars used 2 have been converted to and form part of Class 455/9 EMUs, and 67300 has been preserved.
67300 at the Electric Railway Museum

[1] Colin J Marsden, DMU and EMU Recognition Guide (Ian Allan, 2013) p. 355
[2] Alec Swain, Overhead Line Multiple Units (Ian Allan, 1990) p. 80

Class 23

The success of the revolutionary Deltic diesel engine and the Deltic prototype saw British Railways explore the possibility of putting a single cut-down version of the engine in a smaller mixed-traffic locomotive in the Type B (later 2) power classification. The Class 23 "Baby Deltic" was hence born for services on the Great Northern network [1]. With hindsight the experiment and resulting small fleet of Type 2 locomotives was an unnecessary mistake. There was found to be no real advantage over similar sized locomotives with traditional diesel engines but the Deltic also bought with it extra complexity and cost [2]. The Baby Deltics owed little to their larger brethren except for the engine technology and in design and cab terms owed a lot to the Class 40.

Number built: 10
Built: 1959
Builder: English Electric
Engine: Napier T9-29 Deltic diesel
Power: 1, 100 hp (820 kW)
Formation: Bo-Bo

The fleet was refurbished in 1963 and modernised with a 4 character headcode replacing the original headcode discs and gangway doors [3]. They continued to serve though had high maintenance costs and passengers and crews found they had excessive noise and fumes in operation. With these disadvantages and being such a tiny fleet there was no way the Baby Deltics could survive the fleet rationalisation at the end of the 1960s and all were withdrawn from normal service by 1971. One survived with the Railway Technical Centre and hauled test trains until 1975 [4] but was scrapped like the rest of the class. No Baby Deltics now exist though the Baby Deltic Project aim one day to built a replica.
D5901 at Doncaster in 1959, photographer unknown

[1] John Vaughan, Diesels on the Eastern (Ian Allan, 1982) p. 31
[2] Brian Haresnape, Early Prototype and Pilot Scheme Diesel-Electrics (Ian Allan, 1981) p. 72
[3] Haresnape p. 75
[4] Colin J. Marsden, 25 Years of Railway Research (OPC, 1989) p. 67