British Rail Class 304
The British Rail Class 304 (Originally classed as AM4) were AC electric multiple units designed and produced at British Rail's (BR) Wolverton Works.
| British Rail Class 304 | |
|---|---|
.jpg.webp) 304006 at Manchester Piccadilly in 1992 | |
| In service | 1960 - 1996 |
| Manufacturer | BR Wolverton |
| Order no. |
|
| Family name | 1959 EMU |
| Refurbished | 1980 |
| Number built | 45 |
| Number scrapped | All |
| Formation | |
| Diagram | |
| Design code | AM4 |
| Fleet numbers |
|
| Capacity |
|
| Operator(s) | British Rail |
| Depot(s) | |
| Line(s) served | |
| Specifications | |
| Train length | 246 ft 6 1⁄2 in (75.146 m)[2] |
| Car length |
|
| Width | 9 ft 3 in (2.82 m)[2] |
| Height | 12 ft 4 1⁄2 in (3.772 m)[2] |
| Articulated sections |
|
| Maximum speed | 75 mph (121 km/h)[1] |
| Weight | Total - 151.85 long tons (154.29 t; 170.07 short tons) |
| Traction motors | 4 × BTH[2] 155kW[1] |
| Electric system(s) | 6.25 kV AC and 25 kV 50 Hz AC (OHLE)[2] |
| Current collection method | Pantograph |
| UIC classification | 2'2'+Bo'Bo'+2'2' (1980-) |
| Bogies | Gresley[1] |
| Braking system(s) | Air (EP/Auto) |
| Coupling system | Buckeye[2] |
| Multiple working | Within class and Class 310[2] |
| Track gauge | 1,435 mm (4 ft 8 1⁄2 in) standard gauge |
The Class 304 was produced for BR's new electric suburban services, enabled by the first phases of the West Coast Main Line electrification between Crewe and Manchester/Liverpool/Rugby. The units conformed to the 1959-design for alternating current (AC) electrical multiple units, and were externally very similar to the Class 305, Class 308 and the 1,200 V direct current (DC) Class 504 units.
Following their introduction during the early 1960s, the Class 304 could be found in operation across the length of the West Coast Main Line. Midway through their service life, the units were reclassified as the Class 304 under the TOPS numbering system. The fleet was withdrawn from service during the mid 1990s, largely due to the arrival of cascaded rolling stock such as the British Rail Class 305. Despite efforts to do so, no units survived into preservation, all examples being eventually scrapped.
Production
The first fifteen units were delivered to Longsight Depot, Manchester from April 1960 as four-car sets, and were originally numbered 001-015. Built by British Rail's Wolverton Works, these units were an aesthetic improvement over the AM2 (Class 302) units previously built at York and Doncaster; they featured a new design cab end with a raked back upper area, following a Design Panel recommendation, and emerged in Multiple Unit Green livery, lined out with yellow. Having been immediately preceded on the Wolverton production line by the two-car 1,200 V DC Class 504 units, a considerably high number of design features were shared between the Class 504 and the first AM4 units.
During 1961, production of a further twenty units followed, numbered 016-035, and intended for the Crewe-Liverpool service which commenced on New Year's Day 1962, although as this local service only required three or four units daily they were principally used elsewhere, for services around Manchester and Birmingham. These units differed from the first batch by having a slightly different body design, with wide saloon windows replacing the narrow compartment-style windows. The Motor Brake vehicles had a different internal layout, with 72 second class seats in saloon layout. This improved layout was adopted for the final batch of AM4s,[5] as well as later batches of AM5 (Class 305) units and AM8 (Class 308) units.
The third and final batch of AM4 was another ten units, numbered 036-045, which were almost identical to the second batch and intended for use on the Crewe-Stafford section.
Design
The Class 304 was an interurban electric multiple unit (EMU) train.[6] Its design, which was principally devised to fulfil various requirements laid out by the British Transport Commission, was produced by a team headed by Chief Electrical Engineer S. B. Warder and Chief Mechanical Engineer I. F. Harrison. The units were arranged into four-car sets, consisting of: a Driving Trailer Brake Open vehicle with 82 second class seats (saloon) and a Guard's compartment; a Trailer Composite with 19 first class seats (compartment) and 60 second class seats (saloon), and two toilets; a Motor Brake with 96 second class seats (compartment) and a Guard's compartment; a Driving Trailer with 82 second class seats (saloon), two toilets, and battery equipment.[6] One result of the Motor Brake vehicle having a compartment design was that the window layout on all vehicles was designed to suit, having a narrow window either side of each door.[6]
The body of the vehicle was constructed principally of welded steel.[6] While 16-gauge sheet sections were used for areas such as the bodysides, ends, and roof panels, thinner sections were used in a minority of areas. On some units, fiberglass was inserted into the interior spaces present in the sides, roof, and ends, to provide both thermal insulation and soundproofing; on other units, asbestos was used instead.[6] Additional insulation was sometimes installed beneath the floor panels and the corrugated aluminium floor plate. While much of the passenger compartment's interior finishing was a mixture of timber and plastic, light alloys were used for several elements, such as the doors and luggage racks.[6]
The electrical systems of the Class 304 were largely supplied by a single company, the British manufacturing group Associated Electrical Industries (AEI).[6] Powered by 25 kV AC via catenary, a single pantograph mounted directly above the guard's compartment of the Motor Brake vehicle gathered current from the overhead catenary, which was transferred via a rubber insulated cable from the roof directly to the onboard transformer. This transformer, in combination with a germanium rectifier, stepped down the supplied current and converted it from AC to DC; the use of a germanium rectifier was a novel feature of the type.[6] This system incorporated an automated power control system and voltage selection circuit. The main transformer also supplied an auxiliary feed at 240 V for powering miscellaneous systems on board the train, including the heating units.[6] While the transformer has its own oil-based cooling system, a fan-driven arrangement kept the rectifiers within a safe operating temperature, although relatively little temperature restrictions were present as a consequence of its solid-state nature.[6]
The vast majority of the electrical equipment was installed within bays mounted on the underframe, aside from a single cabinet in the guard's compartment that contained a fuse panel, fault indicator panel, equipment cutout switches, and auxiliary equipment.[6] While most apparatus were installed beneath the motor trailer, including the four AEI-supplied traction motors, the underframe of the driving trailer accommodated some equipment as well, such as the main air compressor, air reservoirs, brake cylinder, and nickel–iron battery units. The rate of acceleration was regulated by a relay that intentionally limited the current.[6] Furthermore, the camshaft would only move when the reverser is set and the motor contacts closed. The motors were protected by an automated cutoff that activated under several circumstances, including excessive oil temperatures, earthing faults, overload, and air supply failure.[6]
The cab was designed to provide the driver with an excellent external view, as well as to be aesthetically pleasing.[6] Glass panels covered the cab's forward section down to waist height while a pair of fully-adjustable seats, for the driver and assistant motorman, were mounted directly upon the rear bulkhead. The driver's instrumentation was fitted upon a sloped panel behind a flat desk lined with push buttons and light switches.[6] To the driver's left was the brake controller while to the right was the master controller. Via the master controller, the driver could operate the vehicle's four motors either together or individually; the latter mode was intended primarily for slow speed shunting operations.[6] The cab walls were lined with plastic panels while the floor was covered in linoleum. Access to the cab was via a single door centrally positioned in the rear bulkhead.[6]
The underframe largely conformed to standard BR designs of the era.[6] It was paired with double-bolster bogies through, which were furnished with knife-edge suspension. Braking was provided via an air-powered arrangement, which featured a self-lapping electro-pneumatic control actuated via a single cylinder.[6] Only the outer ends of each unit featured oleo-pneumatic side-buffers and drop-head automatic couplers; instead, the interior ends of each car were equipped with fixed automatic couplers and lacing side buffers.[6]
Service life
Prior to the commencement of electric services between Crewe and Manchester, the AM4 underwent a period if testing on the Styal line. Somewhat unusually, the AM4s were the only AC units of the 1959 design to wear the lined-out version of Multiple Unit Green livery, with Classes 305 and 308 emerging in comparatively drab plain green. This pleasant appearance was lost, however, when repainted into all-over Rail Blue.
Some of the second batch of AM4s were loaned temporarily to the Eastern Region for use between Liverpool Street and Shenfield/Southend-on-Sea during the conversion of this route from 1,500 V DC to 6.25 kV/25 kV AC, while Class 306 and Class 307 units were being rebuilt. Some of the second batch were also briefly used on the services from Liverpool Street to Hertford East and Bishops Stortford in the mid-1960s.
The AM4 units largely spent their whole careers operating between Crewe and Altrincham via Stockport, or Styal and Manchester, Crewe and Liverpool, Crewe and Birmingham, and Birmingham - Rugby - Northampton. Individual units were occasionally operated to London Euston (notably at the very beginning of electric services, before all the AM10 units were delivered) or Preston, but on rare occasions. Because of their operation on much of the West Coast main line, the units attained substantial mileage at their 75 mph maximum speed each day on their workings, unlike those employed on suburban services elsewhere.
Refurbishment
In the early 1980s, a refurbishment programme was carried out on the units. This included the removal and scrapping of the Trailer Composite vehicles, reducing the units to three-car formation, and the conversion of the Motor Brake vehicles of the first batch (Class 304/1) to saloon layout, reducing seating capacity to 72. Unlike other EMU refurbishment programmes, the work carried out on Class 304 units did not include the fitting of inter-vehicle gangways, or the complete replacement of internal fittings. This meant that original 1960s seats and trim remained in most vehicles, retaining something of their original character. The units were also repainted into blue and grey livery. The loss of one vehicle meant that the power-to-weight ratio of the units increased, thereby improving their performance.
Decline
During the 1980s, the units gradually received the Class '304' TOPS prefix to their unit numbers, and by 1992, several later series units had even received Regional Railways livery. By this time, however, more recently refurbished Class 305 units had become available, displaced from the London, Tilbury and Southend Railway by Class 317s, and with the imminent arrival of brand new Class 323s, the Class 304s began to be withdrawn. The end came for the type in March 1996, with 304002 and 304033 running a series of farewell specials in Birmingham. Known amongst enthusiasts as "Dinosaurs", due to their advancing age, the Class 304 followed their namesakes to extinction.
Preservation attempts
304021 was purchased for preservation in 1998 and was stored in sidings in Crewe. During this time, many windows were smashed, which, as a consequence of the cost of replacing them, led to the abandonment of the project. The long period of storage was due to the difficulty in finding a home on a preserved railway for EMU coaching stock, and thus it became the last of its class to be scrapped in November 2000.[7]
Liveries
References
- Fox 1994, p. 9
- "Class 304". The Railway Centre. Archived from the original on 15 June 2011. Retrieved 31 January 2016.
- "Vehicle Diagram Book No.210 for Electrical Multiple Units (including A.P.T.)" (PDF). Barrowmore MRG. BRB Residuary Ltd. ED203, ED215, EF203, EF204, EG202, EG203. Retrieved 31 January 2016.
- Fox 1987, p. 51.
- "The All Time Guide to EMU Classifications" (PDF). Modern Locomotives Illustrated. Retrieved 1 December 2015.
- "High-Voltage Multiple-Unit Stock for British Railways: Four-car 25-kV 50-cycle suburban trains" (PDF). Associated Electrical Industries. 3 June 1960. Retrieved 20 January 2021.
- "Preservation - 1998". The AC Locomotive Group. Retrieved 1 December 2015.
- "Electric Multiple Unit Stock". Goods & Not So Goods. Archived from the original on 29 August 2016. Retrieved 1 February 2016.
- "Class 304 007 Crewe 030667 CD007". Rail Photoprints. Retrieved 1 February 2016.
- "001 Crewe 24Jul77". Flickr. Retrieved 1 February 2016.
- "1993-06-21 @ Manchester Piccadilly: Class 304 front 75868 61873 75858, rear 75455 61422 75436, Class 142 no. 142077 [slide 14263]". Flickr. Retrieved 1 February 2016.
Sources
- Fox, Peter (1987). Multiple Unit Pocket Book. British Railways Pocket Book No.2 (Summer/Autumn 1987 ed.). Platform 5 Publishing Ltd. ISBN 0906579740. OCLC 613347580.
- Fox, Peter (1994). Electric Multiple Units. British Railways Pocket Book No.4 (7th ed.). Platform 5. p. 9. ISBN 9781872524603.
- Swain, Alec (1990). Overhead Line Electric Multiple Units. British Rail Fleet Survey No.11 (1st ed.). Ian Allan. p. 38.
Further reading
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Wikimedia Commons has media related to British Rail Class 304. |
- "Last-minute rescue bid for West Coast '304' EMU". RAIL. No. 315. EMAP Apex Publications. 8–21 October 1997. p. 67. ISSN 0953-4563. OCLC 49953699.
- "Class 304 EMU plan is floundering". RAIL. No. 322. EMAP Apex Publications. 14–27 January 1998. p. 64. ISSN 0953-4563. OCLC 49953699.
- "Wolverton firm steps in to rescue Class 304 EMU". RAIL. No. 328. EMAP Apex Publications. 8–21 April 1998. p. 66. ISSN 0953-4563. OCLC 49953699.