The British Rail Class 304 (Originally classed as AM4) were
AC electric multiple unit
An electric multiple unit or EMU is a multiple-unit train consisting of self-propelled carriages using electricity as the motive power. An EMU requires no separate locomotive, as electric traction motors are incorporated within one or a numbe ...
s designed and produced at
British Rail
British Railways (BR), which from 1965 traded as British Rail, was a state-owned company that operated most of the overground rail transport in Great Britain from 1948 to 1997. It was formed from the nationalisation of the Big Four British rai ...
's (BR)
Wolverton Works
Wolverton railway works, known locally as Wolverton Works or just The Works, was established in Wolverton, Buckinghamshire, by the London and Birmingham Railway Company in 1838 at the midpoint of the route from London to Birmingham. The line w ...
.
The Class 304 was produced for BR's new electric suburban services, enabled by the first phases of the
West Coast Main Line
The West Coast Main Line (WCML) is one of the most important railway corridors in the United Kingdom, connecting the major cities of London and Glasgow with branches to Birmingham, Liverpool, Manchester and Edinburgh. It is one of the busiest ...
electrification between
Crewe
Crewe () is a railway town and civil parish in the unitary authority of Cheshire East in Cheshire, England. The Crewe built-up area had a total population of 75,556 in 2011, which also covers parts of the adjacent civil parishes of Willaston ...
and
Manchester
Manchester () is a city in Greater Manchester, England. It had a population of 552,000 in 2021. It is bordered by the Cheshire Plain to the south, the Pennines to the north and east, and the neighbouring city of Salford to the west. The t ...
/
Liverpool
Liverpool is a city and metropolitan borough in Merseyside, England. With a population of in 2019, it is the 10th largest English district by population and its metropolitan area is the fifth largest in the United Kingdom, with a popul ...
/
Rugby
Rugby may refer to:
Sport
* Rugby football in many forms:
** Rugby league: 13 players per side
*** Masters Rugby League
*** Mod league
*** Rugby league nines
*** Rugby league sevens
*** Touch (sport)
*** Wheelchair rugby league
** Rugby union: 1 ...
. The units conformed to the 1959-design for
alternating current
Alternating current (AC) is an electric current which periodically reverses direction and changes its magnitude continuously with time in contrast to direct current (DC) which flows only in one direction. Alternating current is the form in whic ...
(AC) electrical multiple units, and were externally very similar to the
Class 305,
Class 308 and the 1,200
V direct current
Direct current (DC) is one-directional flow of electric charge. An electrochemical cell is a prime example of DC power. Direct current may flow through a conductor such as a wire, but can also flow through semiconductors, insulators, or even ...
(DC)
Class 504 units.
Following their introduction during the early 1960s, the Class 304 could be found in operation across the southern and Midland section of the West Coast Main Line. Midway through their service life, the units were reclassified as the Class 304 under the
TOPS
Total Operations Processing System (TOPS) is a computer system for managing railway locomotives and rolling stock, known for many years of use in the United Kingdom.
TOPS was originally developed between the Southern Pacific Railroad (SP), S ...
numbering system. The fleet was withdrawn from service during the early to mid 90s, largely due to the arrival of cascaded rolling stock such as the
Class 305/2 units and new
Class 323
The British Rail Class 323 are electric multiple unit (EMU) passenger trains built by Hunslet Transportation Projects and Holec. All 43 units were built from 1992 through to 1995, although mock-ups and prototypes were built and tested in 1990 ...
units. Despite efforts to do so, no units survived into preservation, all examples being eventually
scrap
Scrap consists of Recycling, recyclable materials, usually metals, left over from product manufacturing and consumption, such as parts of vehicles, building supplies, and surplus materials. Unlike waste, scrap Waste valorization, has monetary ...
ped.
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
Wolverton railway works, known locally as Wolverton Works or just The Works, was established in Wolverton, Buckinghamshire, by the London and Birmingham Railway Company in 1838 at the midpoint of the route from London to Birmingham. The line w ...
, these units were an aesthetic improvement over the AM2 (
Class 302) units previously built at
York
York is a cathedral city with Roman origins, sited at the confluence of the rivers Ouse and Foss in North Yorkshire, England. It is the historic county town of Yorkshire. The city has many historic buildings and other structures, such as a ...
and
Doncaster
Doncaster (, ) is a city in South Yorkshire, England. Named after the River Don, it is the administrative centre of the larger City of Doncaster. It is the second largest settlement in South Yorkshire after Sheffield. Doncaster is situated in ...
; 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, 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
Stafford () is a market town and the county town of Staffordshire, in the West Midlands region of England. It lies about north of Wolverhampton, south of Stoke-on-Trent and northwest of Birmingham. The town had a population of 70,145 in t ...
section.
Design
The Class 304 was an interurban
electric multiple unit
An electric multiple unit or EMU is a multiple-unit train consisting of self-propelled carriages using electricity as the motive power. An EMU requires no separate locomotive, as electric traction motors are incorporated within one or a numbe ...
(EMU) train.
Its design, which was principally devised to fulfil various requirements laid out by the
British Transport Commission
The British Transport Commission (BTC) was created by Clement Attlee's post-war Labour government as a part of its nationalisation programme, to oversee railways, canals and road freight transport in Great Britain (Northern Ireland had the se ...
, 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.
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.
The body of the vehicle was constructed principally of
welded
Welding is a fabrication process that joins materials, usually metals or thermoplastics, by using high heat to melt the parts together and allowing them to cool, causing fusion. Welding is distinct from lower temperature techniques such as braz ...
steel.
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
Fiberglass (American English) or fibreglass (Commonwealth English) is a common type of fiber-reinforced plastic using glass fiber. The fibers may be randomly arranged, flattened into a sheet called a chopped strand mat, or woven into glass cloth ...
was inserted into the interior spaces present in the sides, roof, and ends, to provide both thermal insulation and
soundproofing
Soundproofing is any means of impeding sound propagation. There are several basic approaches to reducing sound: increasing the distance between source and receiver, decoupling, using noise barriers to reflect or absorb the energy of the sound wav ...
; on other units,
asbestos
Asbestos () is a naturally occurring fibrous silicate mineral. There are six types, all of which are composed of long and thin fibrous crystals, each fibre being composed of many microscopic "fibrils" that can be released into the atmosphere b ...
was used instead.
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
alloy
An alloy is a mixture of chemical elements of which at least one is a metal. Unlike chemical compounds with metallic bases, an alloy will retain all the properties of a metal in the resulting material, such as electrical conductivity, ductility, ...
s were used for several elements, such as the doors and luggage racks.
The electrical systems of the Class 304 were largely supplied by a single company, the British manufacturing group
Associated Electrical Industries
Associated Electrical Industries (AEI) was a British holding company formed in 1928 through the merger of the British Thomson-Houston Company (BTH) and Metropolitan-Vickers electrical engineering companies. In 1967 AEI was acquired by GEC, to c ...
(AEI).
Powered by
25 kV AC
Railway electrification systems using alternating current (AC) at are used worldwide, especially for high-speed rail. It is usually supplied at the standard utility frequency (typically 50 or 60Hz), which simplifies traction substations. The d ...
via
catenary
In physics and geometry, a catenary (, ) is the curve that an idealized hanging chain or cable assumes under its own weight when supported only at its ends in a uniform gravitational field.
The catenary curve has a U-like shape, superficia ...
, a single
pantograph
A pantograph (, from their original use for copying writing) is a mechanical linkage connected in a manner based on parallelograms so that the movement of one pen, in tracing an image, produces identical movements in a second pen. If a line dr ...
mounted directly above the guard's compartment of the Motor Brake vehicle gathered current from the overhead catenary, which was transferred via a
rubber
Rubber, also called India rubber, latex, Amazonian rubber, ''caucho'', or ''caoutchouc'', as initially produced, consists of polymers of the organic compound isoprene, with minor impurities of other organic compounds. Thailand, Malaysia, and ...
insulated cable from the roof directly to the onboard
transformer
A transformer is a passive component that transfers electrical energy from one electrical circuit to another circuit, or multiple circuits. A varying current in any coil of the transformer produces a varying magnetic flux in the transformer' ...
. This transformer, in combination with a
germanium
Germanium is a chemical element with the symbol Ge and atomic number 32. It is lustrous, hard-brittle, grayish-white and similar in appearance to silicon. It is a metalloid in the carbon group that is chemically similar to its group neighbors s ...
rectifier
A rectifier is an electrical device that converts alternating current (AC), which periodically reverses direction, to direct current (DC), which flows in only one direction. The reverse operation (converting DC to AC) is performed by an Power ...
, 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.
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.
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.
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
Fuse or FUSE may refer to:
Devices
* Fuse (electrical), a device used in electrical systems to protect against excessive current
** Fuse (automotive), a class of fuses for vehicles
* Fuse (hydraulic), a device used in hydraulic systems to protect ...
panel, fault indicator panel, equipment cutout switches, and auxiliary equipment.
While most apparatus were installed beneath the motor trailer, including the four AEI-supplied
traction motor
A traction motor is an electric motor used for propulsion of a vehicle, such as locomotives, electric vehicle, electric or hydrogen vehicles, elevators or electric multiple unit.
Traction motors are used in electrically powered rail vehicles (ele ...
s, 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
The nickel–iron battery (NiFe battery) is a rechargeable battery having nickel(III) oxide-hydroxide positive plates and iron negative plates, with an electrolyte of potassium hydroxide. The active materials are held in nickel-plated steel tub ...
units. The rate of acceleration was regulated by a
relay
A relay
Electromechanical relay schematic showing a control coil, four pairs of normally open and one pair of normally closed contacts
An automotive-style miniature relay with the dust cover taken off
A relay is an electrically operated switch ...
that intentionally limited the current.
Furthermore, the
camshaft
A camshaft is a shaft that contains a row of pointed cams, in order to convert rotational motion to reciprocating motion. Camshafts are used in piston engines (to operate the intake and exhaust valves), mechanically controlled ignition systems ...
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.
The cab was designed to provide the driver with an excellent external view, as well as to be aesthetically pleasing.
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.
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.
The cab walls were lined with
plastic
Plastics are a wide range of synthetic or semi-synthetic materials that use polymers as a main ingredient. Their plasticity makes it possible for plastics to be moulded, extruded or pressed into solid objects of various shapes. This adaptab ...
panels while the floor was covered in
linoleum
Linoleum, sometimes shortened to lino, is a floor covering made from materials such as solidified linseed oil (linoxyn), Pine Resin, pine resin, ground Cork (material), cork dust, sawdust, and mineral fillers such as calcium carbonate, most com ...
. Access to the cab was via a single door centrally positioned in the rear bulkhead.
The underframe largely conformed to standard BR designs of the era.
It was paired with double-bolster
bogie
A bogie ( ) (in some senses called a truck in North American English) is a chassis or framework that carries a wheelset, attached to a vehicle—a modular subassembly of wheels and axles. Bogies take various forms in various modes of transp ...
s 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.
Only the outer ends of each unit featured
oleo-
pneumatic
Pneumatics (from Greek ‘wind, breath’) is a branch of engineering that makes use of gas or pressurized air.
Pneumatic systems used in Industrial sector, industry are commonly powered by compressed air or compressed inert gases. A central ...
side-buffers and drop-head automatic couplers; instead, the interior ends of each car were equipped with fixed automatic couplers and lacing side buffers.
Service history
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
The history of British Rail's corporate liveries is quite complex. Although from the mid-1960s to the 1980s the organisation was associated with "Rail Blue", a number of other schemes were also used, especially when it was split into operating u ...
.
AM4s of the second batch unit numbers 016 to 023 were loaned to the
Eastern Region for use between
Liverpool Street to
Shenfield
Shenfield is a commuter suburb of Brentwood, in the borough of Brentwood, Essex, England. In 2020, the suburb was estimated to have a population of 5,396.
History
The old village (now town), by the church and Green Dragon pub, lies along the ...
,
Southend Victoria
Southend Victoria railway station is the eastern terminus of the Shenfield to Southend Line in the East of England, a branch off the Great Eastern Main Line, and is one of the primary stations serving the resort city of Southend-on-Sea, Essex (t ...
and
Chelmsford
Chelmsford () is a city in the City of Chelmsford district in the county of Essex, England. It is the county town of Essex and one of three cities in the county, along with Southend-on-Sea and Colchester. It is located north-east of London a ...
after the conversion of the route from 1,500 V DC to 6.25 kV/25 kV (ac) while
Class 306 and
Class 307 units were being rebuilt to 6.25kV/25kV ac. 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
Euston railway station ( ; also known as London Euston) is a central London railway terminus in the London Borough of Camden, managed by Network Rail. It is the southern terminus of the West Coast Main Line, the UK's busiest inter-city railw ...
(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
Between 1984-86 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
Power-to-weight ratio (PWR, also called specific power, or power-to-mass ratio) is a calculation commonly applied to engines and mobile power sources to enable the comparison of one unit or design to another. Power-to-weight ratio is a measuremen ...
of the units increased, thereby improving their performance.
Decline
During the 1980s, the units gradually received the Class '304'
TOPS
Total Operations Processing System (TOPS) is a computer system for managing railway locomotives and rolling stock, known for many years of use in the United Kingdom.
TOPS was originally developed between the Southern Pacific Railroad (SP), S ...
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 305/2 units had become available, displaced from the
London, Tilbury and Southend line
The London, Tilbury and Southend line, also known as Essex Thameside, is a commuter railway line on the British railway system. It connects Fenchurch Street station, in central London, with destinations in east London and Essex, including , , , ...
by
Class 310s, and with the imminent arrival of brand new
Class 323
The British Rail Class 323 are electric multiple unit (EMU) passenger trains built by Hunslet Transportation Projects and Holec. All 43 units were built from 1992 through to 1995, although mock-ups and prototypes were built and tested in 1990 ...
units, 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
Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is t ...
", 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
Crewe () is a railway town and civil parish in the unitary authority of Cheshire East in Cheshire, England. The Crewe built-up area had a total population of 75,556 in 2011, which also covers parts of the adjacent civil parishes of Willaston ...
. 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.
Liveries
* British Railways Green (1960–c.1967)
* BR Blue (c.1967–c.1983), with a yellow rectangle on the cab front (''Chromatic Blue''),
then all-yellow cab front.
* BR Blue and Grey (c.1980–1996)
* Regional Railways (c.1992–1996), "aircraft" blue over white, with a light blue stripe at waist level.
References
Sources
*
*
*
*
*
Further reading
*
*
*
*
{{British Rail EMU
304
Year 304 ( CCCIV) was a leap year starting on Saturday A leap year starting on Saturday is any year with 366 days (i.e. it includes 29 February) that begins on Saturday, 1 January, and ends on Sunday, 31 December. Its dominical letters hence ...
Train-related introductions in 1960
25 kV AC multiple units