British Rail Class 317

British electric passenger trains

4 ft 8+12 in) standard gaugeNotes/referencesSpecifications as at November 1988,[4] except where otherwise noted.

The British Rail Class 317 is an electric multiple unit (EMU) passenger train constructed by British Rail Engineering Limited in two batches: 48 sets were produced in 1981–82 and 24 sets in 1985–87. They were the first of several classes of British Rail EMU to be based on the all-steel Mark 3 bodyshell, departing from the PEP-aluminium design which had spawned the earlier Class 313 to Class 315, Class 507 and Class 508. The Mark 3 bodyshell was also the basis of Class 318, Class 455 and the diesel Class 150. The Class 317 uses overhead alternating current electrification. All units were withdrawn in July 2022.

Description

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Class 317/1

First Capital Connect (ex. WAGN) Class 317 at Welwyn Garden City

The first batch of 48 units was built in 1981–1982 and was classified as Class 317/1. Units were numbered in the range 317301–317348, and had a maximum speed of 100 mph (160 km/h).

Each unit is composed of four vehicles: two unpowered standard-class vehicles with driver's cabs, an intermediate trailer with both first- and standard-class seating, and an intermediate motor vehicle with second-class seating. The motor vehicle also carries the roof-mounted Stone Faiveley AMBR pantograph.

The technical description of the formation of the units is DTSO(A)-MSO-TCO-DTSO(B).[5] Individual vehicles were numbered in the following ranges:

Bodyshells for the TCO vehicles in this batch were constructed at Derby Litchurch Lane Works, while construction of the other bodyshells and overall assembly was carried out at the Holgate Road Carriage Works in York.[5]

The units were built to operate services on the newly electrified London St Pancras to Bedford route and were due to replace the elderly (and unreliable) Class 127 diesel multiple units in October 1982.[5] However, their introduction was delayed until 28 March 1983[6] due to an industrial dispute with the unions over driver-only operation,[7] and the diesel units lingered on until finally being replaced in mid-1983. Units were delivered in the standard livery of BR blue and grey.

In 1986, the route came under control of the Thameslink subsector of newly created Network SouthEast. From 1987, new dual-voltage Class 319 units were introduced on the route, allowing the creation of a new cross-London service, from Bedford to Brighton, via Farringdon and City Thameslink station. The Class 317 units were displaced to outer-suburban services on the WCML out of London Euston to Milton Keynes and Northampton. They replaced the slam-door Class 310 units, which subsequently transferred to the London, Tilbury and Southend railway.

However, the use of Class 317 units out of Euston again proved to be short-lived. In 1989, the second batch of new Class 321 were introduced onto WCML services. The Class 317 units were again displaced, this time to the Great Northern and West Anglia routes out of London King's Cross and London Liverpool Street, where they joined the second batch units. Therefore, for the first time, the entire Class 317 fleet was operating in the same place.

Class 317/2

Class 317/2 in BR Blue and Grey livery

The second batch of 20 units was built in 1985–1986 and were classified as Class 317/2. Units were numbered in the range 317349–317368. A further four units were built in 1987 and numbered 317369–317372. These units have same DTSO(A)-MSO-TCO-DTSO(B) composition as Class 317/1 units, and have vehicles numbered in the following ranges:

All vehicles in this batch were constructed at Holgate Road Carriage Works.

The second batch units were built to operate outer-suburban trains on the Great Northern route from London King's Cross to Stevenage, Cambridge and Peterborough.[8] Like the first batch units, they were delivered in BR Blue/Grey livery. The units replaced the slam-door Class 312 units, dating from 1975, which subsequently transferred to the Great Eastern Main Line and London-Tilbury-Southend routes. Like the DC class 455 units, several aspects of the exterior were modified, with metal hopper ventilators replaced with larger panes of glass and the 'headcode indicator' flat front replaced with a rounded design.

In 1986, the route came under the control of the newly created Network SouthEast, which introduced a bold new blue, red and white livery. The extension of the overhead line equipment soon allowed the units to work services on the West Anglia route from London Liverpool Street to Cambridge. In 1992, electrification spread north from Cambridge to Ely and King's Lynn, allowing the replacement of locomotive-hauled trains.

WAGN Railway refurbished Class 317 at London Liverpool Street. This batch of Class 317 were refurbished during 1998–99 at RailCare, Wolverton Works.

The closely related Class 318 units, which were built for the Ayrshire Coast electrification in Scotland, are effectively a three-car version of the same design, but with a lower speed capability of 90 mph, and with traction motors provided by Brush instead of GEC.

Operations