Train Formation Diagrams

Fig. 1: Gate Stock Train Formations 1903 - 1906

This diagram shows the train formations adopted by the new tube railways which started multiple unit operation in the period 1903 to 1906. The upper diagram shows a Central London Railway train, where the unit indentification lettering would look like this, reading from west to east: ‘B’ DM - T - ‘B’ CT + ‘A’ CT - T - ‘A’ DM. Half the train was the “A” half and the other was the “B” half. Put another way, there was an “A” unit and a “B” unit. Either unit could run as a 3-car train. When being driven from the Control Trailer end, power was provided by the motor car at the rear.

The Central London formation was unique in the way a 3-car unit had the same letters at each end. The orientation was also unique in that "A" units normally faced east and "B" units faced west. The lower diagram shows the LER formation, with the Piccadilly Line as the example. The Bakerloo and Hampstead formations were similar to the Piccadilly but orientated north to south. The same 6-car formation was used for Standard Tube Stock until the introduction of 7-car trains in the late 1920s.

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Fig. 2: 7-car Standard Stock Train Formation

The original, Standard Tube Stock 6-car train formation was increased to 7-cars by the insertion of an additional trailer car and replacing a control trailer with a DM car. Trains were now formed: ‘A’ DM - T - T - ‘D’ DM + ‘A’ CT - T - ‘D’ DM or ‘D’ DM - T - T - ‘A’ DM + ‘D’ CT - T - ‘A’ DM, depending on the line of use and orientation.

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Fig. 3: District Railway Train Formation

The original District Railway eletric stock formation of 1905 is shown in the uypper diagram. The middle motor car (MM) had a cab at each end and could be used to split off a 4-car set at either end of the train. From 1908, control trailers (CTs) were introduced so that either end of the train could run in service. After the first world war, much of the stock was reorganised into a 5+3 formation but eventually, this was developed into a 4+2+2 formation.

The 4+2+2 arrangement looked like this: ‘A’ DM - T - T - ‘D’ DM + T - ‘D’ DM + T - ‘D’ DM. It was developed in the late 1920s and survived until the early 1970s. It suffered from a significant limitation in that there was no driving position at the west end of the 2-car units so all uncoupling was limited in method and location as described later below.

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Fig. 4: 1938 Tube Stock Train Formation

This diagram shows two versions of the 1938 Tube Stock train formation as used between 1938 and 1988. The lower version with the UNDM was seen regularly from the early 1950s. The 1972 Tube Stock currently on the Bakerloo has the same formation with the "A cars facing south and the "D" cars facing north.

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Fig. 5: 1973 Tube Stock and D Stock Train Formation

1973 Tube Stock trains were formed of single-ended 3-car units coupled back to back to form 6-car service trains. The 3-car single-ended units were provided with UNDMs equipped with automatic couplers and shunting control panels. A batch of 20 double-ended 3-car sets were kept for flexibility and to allow a unit to work the (now closed) Aldwych branch.

The D Stock, built from 1978-81 for the District Line, was simply a surface line version of the 73TS. The main fleet was made up of single-ended units and some double-ended units were included to provide flexibility.

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Fig. 6: 1996 Tube Stock Train Formation

This diagram shows the 1996 Tube Stock for the Jubilee. Both '95 and '96 stocks have the 3 + 3 formation with cabs at the outer ends and UNDMs in the middle. There are no double-ended units.

The 1995 Tube Stock on the Northern Line is similar except that the "universal" couplers allow "A" units to couple to other "A" units and likewise with "D" units. The 95TS on the Northern gets turned on the Kennington loop and therefore universal couplers are used to allow “A” ends to couple to other “A” ends as well as “D” ends. The 96TS doesn’t get turned and is “handed” so only “A” ends will couple to “D” ends. Curiously, both stocks are equipped with automatic couplers at the cabs ends.

TRAIN

A train is a connected series of vehicles for rail transport that move along a track (permanent way) to transport freight or passengers from one place to another. The track usually consists of two rails, but might also be a monorail or maglevguideway.

Propulsion for the train is provided by a separate locomotive, or from individual motors in self-propelled multiple units. Most modern trains are powered by diesel locomotives or by electricity supplied by overhead wires or additional rails, although historically (from the early 19th century to the mid-20th century) the steam locomotive was the dominant form of locomotive power. Other sources of power (such as horses, rope or wire, gravity, pneumatics, and gas turbines) are possible.

Types

Steam locomotive-hauled passenger train

German ICE high speed passenger train (a form of multiple unit)

Hungarian Máv-Start Intercity

British Rail Class 153 (single-unit) dieselrailcar

Newag 14WE of Warsaw Urban Rapid Railway in Pruszkow

There are various types of train designed for particular purposes. A train can consist of a combination of one or more locomotives and attached railroad cars, or a self-propelled multiple unit (or occasionally a single powered coach, called a railcar). Trains can also be hauled by horses, pulled by a cable, or run downhill by gravity.

Special kinds of trains running on corresponding special 'railways' are atmospheric railways,monorails, high-speed railways, maglev, rubber-tired underground, funicular and cog railways.

A passenger train may consist of one or several locomotives, and one or more coaches. Alternatively, a train may consist entirely of passenger carrying coaches, some or all of which are powered as a "multiple unit". In many parts of the world, particularly Japan and Europe, high-speed rail is utilized extensively for passenger travel.

Freight trains comprise wagons or trucks rather than carriages, though some parcel and mail trains (especially Travelling Post Offices) are outwardly more like passenger trains.

Trains can also be 'mixed', comprising both passenger accommodation and freight vehicles. Such mixed trains are most likely to occur where services are infrequent, and running separate passenger and freight trains is not cost-effective, though the differing needs of passengers and freight usually means this is avoided where possible.

Special trains are also used for track maintenance; in some places, this is called maintenance of way.

In the United Kingdom, a train hauled by two locomotives is said to be "double-headed", and inCanada and the United States it is quite common for a long freight train to be headed by three or more locomotives. A train with a locomotive attached at each end is described as 'top and tailed', this practice typically being used when there are no reversing facilities available. Where a second locomotive is attached temporarily to assist a train up steep banks or grades (or down them by providing braking power) it is referred to as 'banking' in the UK, or 'helper service' in North America. Recently, many loaded trains in the US have been made up with one or more locomotives in the middle or at the rear of the train, operated remotely from the lead cab. This is referred to as "DP" or "Distributed Power."

[edit]Official terminology

The railway terminology that is used to describe a 'train' varies between countries.

United Kingdom

In the United Kingdom, the interchangeable terms set and unit are used to refer to a group of permanently or semi-permanently coupled vehicles, such as those of a multiple unit. While when referring to a train made up of a variety of vehicles, or of several sets/units, the term formation is used. (Although the UK public and media often forgo 'formation', for simply 'train'.) The word rake is also used for a group of coaches or wagons.

In the United Kingdom Section 83(1) of the Railways Act 1993 defines "train" as follows:

a) two or more items of rolling stock coupled together, at least one of which is a locomotive; or

b) a locomotive not coupled to any other rolling stock.

United States

In the United States, the term consist is used to describe the group of rail vehicles which make up a train. When referring to motive power, consist refers to the group of locomotives powering the train. Similarly, the term trainset refers to a group of rolling stock that is permanently or semi-permanently coupled together to form a unified set of equipment (the term is most often applied to passenger trainconfigurations).

The Atchison, Topeka and Santa Fe Railway's 1948 operating rules define a train as: "An engine or more than one engine coupled, with or without cars, displaying markers."^[2]

[edit]Bogies

Main article: Bogie

US-style railroad truck (bogie) with journal bearings

A bogie (pronounced /ˈboʊɡi/, us dict: bō′·gē) is a wheeled wagon or trolley. Inmechanics terms, a bogie is a chassis or framework carrying wheels, attached to a vehicle. It can be fixed in place, as on a cargo truck, mounted on a swivel, as on a railway carriage or locomotive, or sprung as in the suspension of a caterpillar tracked vehicle.

[edit]Motive power

V43, a common Hungarian electric locomotive used in passenger train service.

The first trains were rope-hauled, gravity powered or pulled by horses, but from the early 19th century almost all were powered by steam locomotives. From the 1910s onwards they began to be replaced by less labour intensive and cleaner (but more complex and expensive) diesel locomotives and electric locomotives, while at about the same time self-propelled multiple unit vehicles of either power system became much more common in passenger service. In most countries dieselisation of locomotives in day-to-day use was completed by the 1970s. A few countries, most notably the People's Republic of China, where coal and labour are cheap, still use a few steam locomotives, but most have been phased out. Historic steam trains still run in many other countries, for the leisure and enthusiast market.

Electric traction offers a lower cost per mile of train operation but at a higher initial cost, which can only be justified on high traffic lines. Since the cost per mile of construction is much higher, electric traction is less favored on long-distance lines with the exception of long-distance high speed lines. Electric trains receive their current via overhead lines or through a third rail electric system.

A recent variation of the electric locomotive is the fuel_cell_locomotive.^[3][4] Fuel cell locomotives combine the advantage of not needing an electrical system in place, with the advantage of emissionless operation. However, the initial cost is still substantial at the moment.