The term Slam-door trains or 'slammers' generally refers to diesel multiple units (DMUs) and electric multiple units (EMUs) that were designed before the use of automatic doors on railway carriages was common. The name came about because of the characteristic noise passengers slamming the doors made when the train was about to depart.

Some slam-door train designs featured doors that could only be opened from the outside, so it was common for passengers to lean out of the window to reach the outside door handle.

'Slam door' trains had many more doors than newer trains (which tend to have only two sets of doors per coach), some designs featured a door for every individual seating bay. Some units had individual compartments, each with its own door and no access to any other part of the train, however, these were unpopular due to security concerns and the lack of access to toilets for longer journeys and many were later converted to standard corridor saloon design.

The term 'slam-door' could also refer to locomotive

Locomotive

A locomotive is a railway vehicle that provides the motive power for a train. The word originates from the Latin loco – "from a place", ablative of locus, "place" + Medieval Latin motivus, "causing motion", and is a shortened form of the term locomotive engine, first used in the early 19th...

-hauled railway coaches that did not have automatic doors, however this usage is less common. The coaches that form part of the High Speed Train

High Speed Train

There are three types of trains in Britain that have been traditionally viewed as high speed trains:* Advanced Passenger Train - Tilting trains which never entered into regular revenue-earning service....

 sets also have doors, but again, the term 'slam-door trains' generally applies to BR Mark 1

British Railways Mark 1

British Railways Mark 1 was the family designation for the first standardised designs of railway carriages built by British Railways. Following nationalisation in 1948, BR had continued to build carriages to the designs of the "Big Four" companies , and the Mark 1 was intended to be the...

 EMUs and DMUs.

History

"Slam-door" EMU and DMU trains were commonplace ever since the introduction of electrification

Electrification

Electrification originally referred to the build out of the electrical generating and distribution systems which occurred in the United States, England and other countries from the mid 1880's until around 1940 and is in progress in developing countries. This also included the change over from line...

. While there were early examples of the type, which are beyond the scope of this example, they became commonplace on the Southern Railway

Southern Railway (Great Britain)

The Southern Railway was a British railway company established in the 1923 Grouping. It linked London with the Channel ports, South West England, South coast resorts and Kent...

 in the 1930s when it electrified its main routes around the South of London

London

London is the capital city of :England and the :United Kingdom, the largest metropolitan area in the United Kingdom, and the largest urban zone in the European Union by most measures. Located on the River Thames, London has been a major settlement for two millennia, its history going back to its...

 at 750VDC (third rail

Third rail

A third rail is a method of providing electric power to a railway train, through a semi-continuous rigid conductor placed alongside or between the rails of a railway track. It is used typically in a mass transit or rapid transit system, which has alignments in its own corridors, fully or almost...

), in particular, the line to Brighton

Brighton

Brighton is the major part of the city of Brighton and Hove in East Sussex, England on the south coast of Great Britain...

.

Slam-door diesel multiple units became common in the 1950s when British Railways (BR) sought to modernise its network and do away with steam locomotives. Many one, two and three coach units were built for non-electrified lines all around the country, in particular, these were popular on branch lines where it was uneconomic to electrify. These units were later classified in the Class 101 - 129 series, dependent on the design.

Meanwhile, large new fleets of electric slam-door trains were being built for use around the country. AC units were built for the newly-electrified routes to Southend-on-Sea

Southend-on-Sea

Southend-on-Sea is a unitary authority area, town, and seaside resort in Essex, England. The district has Borough status, and comprises the towns of Chalkwell, Eastwood, Leigh-on-Sea, North Shoebury, Prittlewell, Shoeburyness, Southchurch, Thorpe Bay, and Westcliff-on-Sea. The district is situated...

, Colchester

Colchester

Colchester is an historic town and the largest settlement within the borough of Colchester in Essex, England.At the time of the census in 2001, it had a population of 104,390. However, the population is rapidly increasing, and has been named as one of Britain's fastest growing towns. As the...

 and Clacton and for the Glasgow

Glasgow

Glasgow is the largest city in Scotland and third most populous in the United Kingdom. The city is situated on the River Clyde in the country's west central lowlands...

 area; also for some routes around Manchester

Manchester

Manchester is a city and metropolitan borough in Greater Manchester, England. According to the Office for National Statistics, the 2010 mid-year population estimate for Manchester was 498,800. Manchester lies within one of the UK's largest metropolitan areas, the metropolitan county of Greater...

. These AC units were later classified as British Rail Class 302

British Rail Class 302

The British Rail Class 302 was a type of electric multiple unit introduced between 1958 - 1960 for outer suburban passenger services on the London, Tilbury and Southend Railway route...

 through to British Rail Class 312

British Rail Class 312

The British Rail Class 312 is a type of alternating current electric multiple unit built in 1975-1978 for use on outer-suburban passenger services. It was the last class of multiple unit to be constructed with the British Rail Mark 2 bodyshell, and also the last with slam doors...

, again dependent on the design.

In the Southern region, the early units were replaced in the 1950s and 60s with new slam-door third-rail electric units, first of all the compartment commuter units '4-SUB

British Rail Class 405

Under the British Rail TOPS computer system, Class 415 was allocated to surviving examples of the Southern Railway 4-Sub Class electric multiple units built between 1941 and 1951...

' and '4-EPB' (BR Class 415

British Rail Class 415

British Rail Class 415 was a suburban 750 V DC third rail electric multiple unit commissioned by the Southern Region of British Railways. Built between 1951 and 1957, it became the most numerous class on the region after the withdrawal of the 4Subs...

) and later the much more comfortable longer distance trains which survived in use until the early years of the 21st century. These included the '4-CIG' British Rail Class 421

British Rail Class 421

The British Rail Class 421 electrical multiple units were built at BR York Works between 1964 and 1972. Units were built in two batches, and were initially introduced on services on the Brighton Main Line. Later units were introduced on services to Portsmouth. These units replaced older Southern...

), '4-CEP' (British Rail Class 411

British Rail Class 411

The British Rail Class 411 electrical multiple units were built at Eastleigh works from 1956-63 for the newly electrified main lines in Kent. These units were based on the earlier Southern Railway 4Cor design, built in 1937. They were replaced by Juniper units.-Description:A total of 133 units...

) and '4-VEP' (British Rail Class 423

British Rail Class 423

The British Rail Class 423 electrical multiple units were built by BR at York Works from 1967 to 1974, although the MBSOs and TSOs of the first 20, 7701-7720, were constructed at Derby Works. They feature manually-opening doors next to every seating row and were the last coaching stock built in...

); the former two being fairly similar while the latter was designed with more crowded seats and more doors to enable faster unloading and loading of passengers.

Finally, also on the Southern division of British Rail, new slam-door diesel multiple units were introduced in the late 1950s, these were classified as British Rail Class 201

British Rail Class 201

The British Rail Class 201 six-car diesel-electric multiple units were built in 1957-1958 at Eastleigh and Ashford. They were built for use on the London-Hastings line...

 and similar and were affectionately named 'Thumpers' due to the distinctive noise they made.

Demise

The slam-door trains have had a long and robust service life, with several units still in operation on public rail services (2009) but have gradually became replaced by newer units with automatic doors. These newer units were cheaper to maintain and safer as the doors were locked centrally. This facility, via a form of central locking has now been fitted to surviving public rail line units. In the past, slam-door trains' doors could be opened at any time, even while the train was still moving into the station.

The introduction of the British Rail Class 313

British Rail Class 313

British Rail Class 313 electric multiple units were built by BREL at York Works between February 1976 and April 1977 and were the first second-generation EMUs to be constructed for British Rail...

 AC EMUs and later derivitaves of this class in the late 1970s and early 1980s saw the beginning of the end for the AC slam door trains. The very similar British Rail Class 455

British Rail Class 455

The British Rail Class 455 is a type of electric multiple unit drawing power from a 750 V DC third rail. Built by BREL at York works in the early and mid-1980s, they were initially categorised as Class 510 as the successor to the Class 508...

 trains around London displaced the 4-EPBs while introduction of the '5-WES' (British Rail Class 442

British Rail Class 442

The British Rail Class 442 Wessex Electric electrical multiple units were introduced in 1988 on the South Western Main Line from London Waterloo to Southampton Central, Bournemouth, Poole and Weymouth. Twenty-four of these 5-car units were built in 1988/89 by BREL at its Derby works...

) 'Wessex Electrics' in 1988 and electrification of the line to Weymouth

Weymouth railway station

Weymouth railway station is a railway station serving the town of Weymouth, Dorset, England. The station is the terminus of both the South Western Main Line from London Waterloo and the Heart of Wessex Line from and .-History:...

 saw the end of yet more slam-door trains.

At the same time, BR had introduced a new type of DMU, the British Rail Class 150

British Rail Class 150

The British Rail Class 150 "Sprinter" diesel multiple units were built by BREL from 1984-87. A total of 137 units were built in three main subclasses, replacing many of the earlier first-generation "Heritage" DMUs.- Background :...

 'Sprinter', which gave the slam-door DMUs a run for their money.

However, there was one factor that was far more important than this in the demise of the slam-door trains and that was safety. While the units featured a relatively sturdy steel underframe chassis, the body was usually just a framework covered with thin steel panelling. The Clapham Junction disaster in the later 1980s, where lives were lost after two slam-door trains collided and broke up was the final nail in the coffin, however, it took nearly fifteen years for the last slam-door train to be withdrawn from mainline services.

The development of a new generation of multiple units in the early 2000s enabled the now-privatised train operators to finally replace the slam-door trains (which were over 40 years old in some cases) with modern, new units. These included Virgin Voyager and British Rail Class 170 TurboStar DMUs and Siemens

Siemens

Siemens may refer toSiemens, a German family name carried by generations of telecommunications industrialists, including:* Werner von Siemens , inventor, founder of Siemens AG...

 Desiro and Pendolino

Pendolino

Pendolino is an Italian family of tilting trains used in Italy, Spain, Portugal, Slovenia, Finland, Russian Federation, the Czech Republic, the United Kingdom, Slovakia, Switzerland, China and shortly in Romania and Poland...

 EMUs.

Preservation

The last units were withdrawn from the mainline railway network in 2004, and South West Trains

South West Trains

South West Trains is a British train operating company providing, under franchise, passenger rail services, mostly out of Waterloo station, to the southwest of London in the suburbs and in the counties of Surrey, Hampshire, Dorset, Devon, Somerset, Berkshire, and Wiltshire and on the Isle of Wight...

 ran slam-door trains on the Lymington

Lymington

Lymington is a port on the west bank of the Lymington River on the Solent, in the New Forest district of Hampshire, England. It is to the east of the South East Dorset conurbation, and faces Yarmouth on the Isle of Wight which is connected to it by a car ferry, operated by Wightlink. The town...

 branch line in Hampshire until 22 May 2010 . It had taken two '4-CIG' (British Rail Class 421

British Rail Class 421

The British Rail Class 421 electrical multiple units were built at BR York Works between 1964 and 1972. Units were built in two batches, and were initially introduced on services on the Brighton Main Line. Later units were introduced on services to Portsmouth. These units replaced older Southern...

) units and installed central locking and ran the service as a 'heritage line'. This was the only place you could travel on a slam-door electric train in the UK nowadays, although some units have been converted for departmental use.

South West Trains has also retained a complete '4-VEP' (British Rail Class 423

British Rail Class 423

The British Rail Class 423 electrical multiple units were built by BR at York Works from 1967 to 1974, although the MBSOs and TSOs of the first 20, 7701-7720, were constructed at Derby Works. They feature manually-opening doors next to every seating row and were the last coaching stock built in...

) unit which is in storage. Other examples of slam door trains are held by various museums and private groups, however there are no remaining examples of some types of the units, with the AC electric units having fared particularly badly. Slam-door electric trains are generally unattractive to preserved railways as they are unable to run under their own power while diesel units remain in service on many preserved railways around the UK.

Two British Rail Class 121

British Rail Class 121

Sixteen Class 121 single-car driving motor vehicles were built from 1960, numbered 55020–55035. These were supplemented by ten trailer vehicles, numbered 56280–56289 . They had a top speed of 70 mph, with slam-doors, and vacuum brakes...

 "Bubblecar" single coach DMUs are still in use on the mainline railway network, these are on the very short branch line between Cardiff

Cardiff

Cardiff is the capital, largest city and most populous county of Wales and the 10th largest city in the United Kingdom. The city is Wales' chief commercial centre, the base for most national cultural and sporting institutions, the Welsh national media, and the seat of the National Assembly for...

 and Cardiff Bay

Cardiff Bay

Cardiff Bay is the area created by the Cardiff Barrage in South Cardiff, the capital of Wales. The regeneration of Cardiff Bay is now widely regarded as one of the most successful regeneration projects in the United Kingdom. The Bay is supplied by two rivers to form a freshwater lake round the...

 and on the Aylesbury to Princes Risborough line, which only operates at peak times.

Another problem is that many units contain asbestos

Asbestos

Asbestos is a set of six naturally occurring silicate minerals used commercially for their desirable physical properties. They all have in common their eponymous, asbestiform habit: long, thin fibrous crystals...

. This was removed from some when they were refurbished in the 1980s but a lot of slam-door trains were incinerated to destroy the asbestos. Those that remain have to be treated by anyone that wished to purchase them, which is a very expensive process that also damages the units.

As of 2006, a significant number of DC slam-door EMUs were stored at Pig's Bay in Shoeburyness

Shoeburyness

Shoeburyness is a town in southeast Essex, England, situated at the mouth of the river Thames Estuary. It is within the borough of Southend-on-Sea, and is situated at the far east of the borough, around east of Southend town centre...

, Essex

Essex

Essex is a ceremonial and non-metropolitan county in the East region of England, and one of the home counties. It is located to the northeast of Greater London. It borders with Cambridgeshire and Suffolk to the north, Hertfordshire to the west, Kent to the South and London to the south west...

, however it is unknown if they are still there.