British Rail Classes 445 and 446

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British Rail Class 445 and 446
4PEP unit No.4002 in the sidings at Wimbledon depot
In service	1971-1980
Manufacturer	BREL
Order no.	30818 (DMSO, 445, 446) 30819 (MSO, 445)[1]
Built at	BREL York
Family name	1972 design (PEP)[2]
Constructed	1971
Entered service	1973[1]
Number built	2 × 4-car (445) 1 × 2-car (446)
Number scrapped	All
Formation	2/4 cars per trainset: DMSO+MSO+MSO+DMSO (445) DMSO+DMSO (446)
Diagram	861 (DMSO, 445, 446) 862 (MSO, 445)[1]
Design code	PEP
Fleet numbers	4001-4002 (445, set) 2001 (446, set) 64300-64305 (DMSO, 445, 446) 62426-62429 (MSO, 445)
Capacity	280 (445) 136 (446) 68S (DMSO) 72S (MSO)[1]
Operators	British Rail
Specifications
Train length	264 ft 10 in (80.72 m) (445) 132 ft 5 in (40.36 m) (446)
Car length	64 ft 11+1⁄2 in (19.799 m) (DMSO) 65 ft 4+1⁄4 in (19.920 m) (MSO)[1]
Width	9 ft 3 in (2.82 m)[1]
Height	11 ft 6+1⁄2 in (3.518 m)
Doors	Bi-parting sliding
Maximum speed	75 mph (121 km/h)
Weight	31 long tons 6 cwt (31.8 t) (DMSO, 64305) 35 long tons 7 cwt (35.9 t) (DMSO, others) 34 long tons 6 cwt (34.9 t) (MSO)[1]
Traction motors	4 × GEC[1] (per car)
Power output	4 x 100 hp (75 kW) (per car) 1,600 hp (1,200 kW) (445, total) 800 hp (600 kW) (446, total)
Electric system(s)	750 V DC third rail
Current collector(s)	Contact shoe
Bogies	BREL BP8 (2001)[3] BREL BT5 (4001) Mk6 (4002, 446) F-type (64305)[1]
Braking system(s)	Air EP/rheostatic (445) Air, rheostatic (446)
Coupling system	Scharfenberg (outer) Bar (inner)
Multiple working	Within type only
Track gauge	1,435 mm (4 ft 8+1⁄2 in) standard gauge

The PEP (Prototype Electro Pneumatic Train) Stock were prototype electric multiple units used on British Rail's Southern and Scottish Regions during the 1970s and early 1980s. They were forerunners of the British Rail Second Generation electric multiple unit fleet. Three units were built, one two-car unit (2001), and two four-car units (4001/4002). Under TOPS, the driving cars were originally classified as Class 461 with the non-driving motor cars as Class 462.^[1] They were later reclassified as Class 445 (4PEP) and Class 446 (2PEP).

Internal layout was for commuter services; low-backed, bus-style 2+2 seating in open saloons, wide gangways with hanging straps, and no lavatory facilities. They were the first electric multiple units designed by British Rail with electric sliding doors,^[4] outside the Scottish Region. They were unable to operate with any other stock due to their new coupling system.^[5] Externally, 2001 was finished in unpainted aluminium, while 4001/4002 were painted in all-over Rail Blue.^[6] In passenger use, they normally operated together as a ten-car formation.

On the 4-PEP units the non-driving cars were powered, similar to London Underground practice at the time, but a departure from previous British Railways designs where there had not been any 4-car units with all axles powered.^[7] Also introduced for the first time was rheostatic braking with cam-controlled analogue logic, and fluorescent lighting working at 50 Hz. Interior design was open saloons with 2+2 seating, although this was not considered to be finalised until after trial running, and also included communicating doors between coaches and between units, with the driving cars having 2 pairs of sliding doors each and 3 pairs on the non-driving coaches.^[7]

All three units were initially assigned to the South Western Division of the Southern Region, based at Wimbledon Park and Strawberry Hill. Upon arrival, they were used under an extensive testing programme prior to entering full passenger service in June 1973, on services from Waterloo to Chessington South, Hampton Court and Shepperton. In August 1973, all three units were moved to the South Eastern Division, where they worked services from Cannon Street/Charing Cross to Bromley North, Dartford and Sevenoaks. Although capable of being used as a single 10-car formation on the SED, a number of failures saw them returned to the SWD after a month.

After the units were withdrawn from passenger service, they continued to be used by the Research department for further tests.^[8] For this purpose, the units and individual carriages were all renumbered into the departmental series. The two Class 446 power cars were teamed with a newly built pantograph trailer and became TOPS Class 920, number 920001.^[5] This was then used for the development of Classes 313–315.^[9] The two Class 445 four car sets became TOPS Class 935, numbered 056 and 057 in the Southern Region departmental (non-revenue earning) unit series. 056 saw little use, being stored at Wimbledon Park until June 1980, when it was transferred to the Railway Technical Centre at Derby.

The production-run classes which are most visibly similar to the prototype Stock are the dual voltage 750 V DC / 25 kV AC Class 313, the 25 kV AC Classes 314 and 315, and the 750 V DC Classes 507 and 508. It was also planned that the rolling stock for the services through the proposed Picc-Vic tunnel, intended as Class 316, would have formed part of the PEP family.^[10] However, subsequent builds have also drawn heavily on the experience gained by this stock.

The PEP units had three sets of sliding doors on each of the non-driving cars for handling dense inner-suburban traffic. However, the Class 313 and all subsequent builds, including later Mark 3-based units, have only had two sets of doors per car.

All three units were finally taken out of use in the mid-1980s. None of the cars have survived; 920001 was scrapped in 1987, 056 in 1986 and 057 in 1990.

The unit formations in passenger and departmental service were:

• Longworth, Hugh (2015). British Railways Electric Multiple Units to 1975. Oxford Publishing Co. ISBN 9780860936688. OCLC 923205678.
• Marsden, Colin J. (1984). Departmental Stock. Rolling stock recognition. Vol. 3. Ian Allan. ISBN 9780711014466. OCLC 15107222.

• Ball, N. D. (1972). "The BR High-Density Prototype Electric Multiple Unit Stock". Railway Engineering Journal. 1 (1). London: the Institution of Mechanical Engineers: 21–37. ISSN 0048-6515. OCLC 1559754.
• Marsden, Colin J. (1982). EMUs. Motive Power Recognition. Vol. 2. Ian Allan. pp. 134–136. ISBN 9780711011656. OCLC 16537600.

• Media related to British Rail Classes 445 and 446 at Wikimedia Commons