Push–pull train

Source: Wikipedia, the free encyclopedia.
(Redirected from
Autotrain
)
Not to be confused with Top and tail.

In a push–pull train, locomotives at both ends of a train can be used at the same time, controlled by one driver.
When using a single locomotive, a control car with duplicate controls can be used when pushing.
A push–pull train with two control cars and a locomotive in the middle

Push–pull is a configuration for locomotive-hauled trains, allowing them to be driven from either end of the train, whether having a locomotive at each end or not.

A push–pull train has a locomotive at one end of the train, connected via some form of remote control, such as multiple-unit train control, to a vehicle equipped with a control cab at the other end of the train. This second vehicle may be another locomotive, or an unpowered control car. This formation meant that the locomotive would not have to run-around at the end of a journey before returning.

The trains were also historically knows as "motor trains" or "railmotors", but the term "railmotor" is now used to refer to trains where the locomotive was integrated into a coach. In the UK and some other parts of Europe, the control car is referred to as a driving trailer (or

driving van trailer
/DVT where there is no passenger accommodation); in the US and Canada, they are called cab cars and in Australia, they are called driving trailers.

Train formation

Locomotive at one end

Multiple unit trains
Subtypes
Technology
By country
Push–pull train in Austria (2004); note locomotive at the rear of the train.
Push–pull train in the Czech Republic (2016); note control car at the rear of the train.
Former Push–pull train of Deutsche Reichsbahn (control car out of function) after the unification of Germany
A modern driving van trailer in Ireland
Push–pull train in Slovakia

Historically, push–pull trains with steam power provided the driver with basic controls at the cab end, including the regulator, brake and whistle. The cab would also be provided with a bell or other signalling code system to communicate with the fireman, who remained on the locomotive to tend to the fire, in order to pass commands to adjust controls not available in the cab.

At low speeds, some push–pull trains are run entirely from the engine with the guard operating bell codes and brakes from the leading cab when the locomotive is pushing the train.

Many mountain railways also operate on similar principles in order to keep the locomotive lower down than the carriage to prevent any opportunity for a carriage to run away from a train down the gradient and also so that even if the locomotive ever ran away, it would not take the carriage with it.

Modern train control systems use sophisticated electronics to allow full remote control of locomotives. Nevertheless, push–pull operation still requires considerable design care to ensure that control system failure does not endanger passengers and also to ensure that in the event of a derailment, the pushing locomotive does not push a derailed train into an obstacle, worsening the accident. The 1984 Polmont rail accident, in Scotland, occurred when a push–pull train struck a cow on the track.

When operating push–pull, the train can be driven from either the locomotive or the alternative cab. If the train is heading in the direction in which the locomotive end of the train is facing, this is considered 'pulling'. If the train is heading in the opposite direction, this is considered 'pushing' and the

terminus
.

Two locomotives

New Jersey Transit train with Bombardier ALP-46 locomotives on both ends and 11 cars in between, in New Jersey
, United States

Alternatively, a push–pull train, especially a long one, may have a locomotive on each end so that there is always one locomotive pushing and one locomotive pulling. In this case, caution must be used to make sure that the two locomotives do not put too much stress on the

New Jersey Transit's longest Northeast Corridor Line multilevel
trains.

This form of operation has not necessarily been a function of train length; sometimes it was the most convenient way to set up push–pull operation in pre-HEP days without converting coaches to cab control operation. A prime example of this was the

non-electric commuter operation, with a pair of EMD FP7 diesels bracketing a single five-car train, to supplant the Reading's fleet of RDCs. This train normally operated a weekday peak-hour round trip between Reading Terminal, Philadelphia and Reading, Pennsylvania, from the late 1960s until 1981, with operation in the last five years by Conrail under contract to SEPTA.[1]

Locomotive in the middle

Golden Pass Panoramic train in Switzerland with locomotive in the middle

A rare but possible configuration has a locomotive in the middle of the train with control cars at both ends, as was, for instance, used for a time on the Brussels–Amsterdam

ERTMS train control system in use on the Belgian HSL 4 and the Dutch HSL-Zuid. The Class 28 TRAXX locomotives
were later upgraded, and the service went back to "normal" push–pull operation.

A preserved GWR autotrain, running with the locomotive sandwiched between two driving coaches on the South Devon Railway.

Historically, the Great Western Railway ran Autotrains with two driving coaches sandwiching a steam locomotive.[citation needed]

Distributed power

Main article: Distributed power

In this configuration, locomotives hauling a train are located other than at the front or the back. It may include remote control locomotives in the middle of a train. If operational considerations or economics require, trains can be made longer if intermediate locomotives are inserted in the train and are remotely controlled from the leading locomotive.

History

Great Britain

Steam

GWR Autocoach
capable of steam push–pull operation
Great Western Railway
Main article:
GWR Autocoach

The first company to use the system was the

Brentford Branch Line (between Southall and Brentford) as an experimental substitute for steam railcars. Control was by rodding and the mechanism allowed the driving compartment to be either one or two carriages-distant from the engine. With the engine in the middle of a formation, up to four carriages could be used. To reduce the surprise of a locomotive at the "wrong" end of its train, some were initially fitted with panelling painted in carriage livery.[2]
The experiment was successful and the company's remaining railcars were gradually converted for autotrain use and purpose-built units constructed.

Other railways

Other companies followed the lead in 1905: the

London, Brighton & South Coast Railway using a compressed-air method of control and the Midland Railway, using a cable-and-pulley mechanism. The Great Central deployed the trains in 1906, using cable controls similar to that of the Midland. By the 1920s, most companies had them and they remained in use until they were replaced by diesel multiple units (DMUs) in the 1950s.[2]

Electric and diesel

Network Rail Driving Brake Standard Open in October 2009

In 1967, the

London Waterloo to Bournemouth, which were operated by electro-diesel locomotives.[2][3]

In the early 1970s, the

London Liverpool Street and Norwich, where they were modified to work with Class 86
electric locomotives.

The original system of using the Blue Star multiple working was later revived after

Abellio Greater Anglia, Arriva Trains Northern, Northern Rail and Arriva Rail North with Class 37s all with Mark 2 carriages.[5][6][7][8] The same system was also adopted by Network Rail for its track observation trains, although on many trains one locomotive has recently been replaced by a DBSO modified to work with Blue Star.[9]

Driving Van Trailers (DVTs)

A GNER Mark 4 Driving Van Trailer at Alnmouth in June 2005
Main article: Driving Van Trailer

In 1988, 52 Mark 3 Driving Van Trailers were built by British Rail Engineering Limited to allow it to replace life expired electric locomotives on the West Coast Main Line. These operated with Mark 2 and Mark 3 sets.[10]

As part of the electrification of the East Coast Main Line, 31 Mark 4 Driving Van Trailers were built in the late 1980s by Metro-Cammell to operate with Mark 4s coaches at the south end of the InterCity 225 sets. Some of these passed to Transport for Wales Rail in 2021 to work on their Holyhead to Cardiff Premier Service.

In the 2000s, some Mark 3s have been modified to operate with Class 67 locomotives with Arriva Trains Wales, Chiltern Railways and Wrexham & Shropshire.

In 2019, new Mark 5 carriages, one of which has a cab, entered service with Class 68 locomotives for TransPennine Express, in a push–pull configuration.

Ireland

2600 Class DMUs
.

Iarnród Éireann employs push–pull trains of two different kinds. The first of these were built in 1996. These are

201 Class
locomotives.

The other type of push–pull train used in Ireland is the Mark 4 type (not to be confused with the British Rail Mark 4 type). These sets, delivered in 2005–2006, are used exclusively on the Dublin to Cork route, again operated by 201 Class locomotives.

Between 1980 and 2009, Iarnród Éireann operated push–pull sets based on the British Rail Mark 3 design, with a non-gangwayed driving cab fitted.[11] These were operated with 201 Class locomotives, although in the past

Dublin Heuston
after the introduction of railcar sets elsewhere. The entire Mark 3 fleet was withdrawn in September 2009 and scrapped in 2014.

France

In June 1958, SNCF commenced operating steam trains in push–pull formation out of Gare de l'Est.[12]

North America

the Greater Miami area (Tri-Rail); the San Francisco Bay Area (Caltrain and ACE); Southern California (Metrolink and Coaster); Toronto (GO Transit); Montreal (AMT); and the Wasatch Front in Utah (UTA FrontRunner). Most of these systems (except for SEPTA and Metro-North) continue to utilize some type of bi-level passenger cars
for push–pull service, either partially or exclusively.

Amtrak has a number of converted Metroliner EMUs in service as cab cars on the Keystone Corridor, where they operate in conjunction with ACS-64 electric locomotives. In addition, many regional services, such as the Michigan Services,

San Joaquin, and Pacific Surfliner
services in California are operated in push–pull configuration using purpose-built cab cars and diesel locomotives.

The

E50C
electric locomotives that ran backwards from the coal-fired powerplant they served to the mine where their trains were loaded by affixing bogie trucks, a headlight, and a horn to the last freight car on each train.

Israel

A GEC–Alsthom push–pull of Israel Railways (IR)

In 1996, Israel Railways began running GEC–Alsthom push–pull coaches. Since then, it has also acquired push–pull coaches from Bombardier and Siemens. As of 2016, the bulk of Israel Railways' passenger operations use push–pull coaches. All of them have one locomotive at one end and a control car at the other end.

Australia

The New South Wales XPT long-distance passenger trains used by NSW TrainLink operate in a push–pull operation. In the past V/Line operated P class push–pulls on interurban services to Bacchus Marsh and Wyndham Vale until 2017. South Australian Railways' 2000 class DMUs could be found with at least one motor car and one cab car in a push–pull configuration until their withdrawal in 2016.

New Zealand

Lower Hutt
, 1906 with motor train

In the first quarter of the 20th century up to 13 motor trains ran on NZR.[14]

Until 2015, the Auckland suburban network run by Transdev used rebuilt British Rail Mark 2 carriages in either four, five or six car configurations. Three to five SA class carriages and an SD class driving carriage, fitted with a cab, were coupled to a DC class (4- and 5-car) or DFT/DFB class (6-car) locomotive, leased from KiwiRail.

All SA and SD class cars were rebuilt by

DBR class
locomotives.

Following electrification of most of the Auckland suburban railway network, these diesel units have been replaced by a modern electrical fleet that consist of one or two sets of 3 car units (each of which have one carriage that can service passengers with disabilities).

See also

Wikimedia Commons has media related to Push-pull trains.

References

  1. ISBN 0-9602080-0-3
    .
  2. ^
    ISBN 0-19-211697-5
    .
  3. ^ "Pull and push to Bournemouth". Railway Gazette. No. 7 July 1967. p. 481.
  4. ISBN 0-7110-2689-0
    .
  5. Rail Magazine
    . No. 481. 18 February 2004. p. 63.
  6. Rail Magazine
    . No. 447. 30 October 2002. p. 12.
  7. Rail Magazine
    . No. 773. 29 April 2015. p. 28.
  8. Rail Express
    . No. 87. August 2003. p. 5.
  9. ^ "Network Rail buys four DBSOs". Today's Railways UK. No. 64. April 2007. p. 70.
  10. ^ "Met-Cam scoops MkIV contract". Railway Gazette International. No. February 1987. p. 73.
  11. ^ RP Grainger (1990). "Push–pull trains for Iarnród Éireann – Irish Rail". Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit. 204 (16). Prof Eng Publishing: 21–30.
    S2CID 111243351
    .
  12. ^ "Push-and-Pull Trains". Railway Gazette. No. 8 May 1959. p. 533.
  13. ^ "C&NW Plans Push-Pull Commuting". Railway Age. No. 21 April 1958. pp. 17–19.
  14. ^ "Appendix to the Journals of the House of Representatives | 1925 Session I". paperspast.natlib.govt.nz. Retrieved 10 May 2018.

Further reading
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