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An island platform (also center platform, centre platform) is a station layout arrangement where a single platform is positioned between two tracks within a railway station, tram stop or transitway interchange. Island platforms are popular on twin-track routes due to pragmatic and cost-effective reasons. They are also useful within larger stations where local and express services for the same direction of travel can be provided from opposite sides of the same platform thereby simplifying transfers between the two tracks. An alternative arrangement is to position side platforms on either side of the tracks.

Contents

1 Layout 2 Advantages and tradeoffs 3 Examples 4 Unused sides of island platforms 5 Gallery 6 See also 7 References

Layout[edit]

Island platform

Legend

Two tracks and one island platform

This section needs expansion. You can help by adding to it. (March 2017)

The historical use of island platforms depends greatly upon the location. In the United Kingdom the use of island platforms is relatively common when the railway line is in a cutting or raised on an embankment, as this makes it easier to provide access to the platform without walking across the tracks. Advantages and tradeoffs[edit] The island platform layout is a popular, cost-effective and practical solution in modern railway systems. Island platforms allow facilities such as escalators, elevators, shops, toilets and waiting rooms to be shared between both tracks rather than being duplicated or present only on one side. This is essential for wheelchair accessible stations. An island platform makes it easier for wheelchair users and other people with physical disabilities to change services between tracks. Additionally, an island platform layout eliminates the need to construct a crossover or subway between two platforms. However, island platforms may become overcrowded, especially at busy stations, and this can lead to safety issues such as Clapham Common (see image) and Angel (now rebuilt) on the London Underground
London Underground
(as well as Union (now rebuilt) on the Toronto subway
Toronto subway
and Umeda on the Osaka Municipal Subway). However, for the tracks to diverge around the center platform, extra width is required along the right-of-way on each approach to the station, especially on high-speed lines. Track centers vary for rail systems throughout the world but are normally 3 to 5 meters (10 to 16 ft). If the island platform is 6 meters (20 ft) wide, the tracks have to slew out by the same distance. While this is not a problem on a new line that is being constructed, it makes it impossible to build a new station on an existing line without altering the tracks. In addition, a single island platform makes it quite difficult to have through tracks (used by trains that do not stop at that station), which are usually between the local tracks (where the island would be).

Clapham Common station on the London
London
Underground's Northern line

Fast and slow tracks

Legend

Four tracks and two island platforms

A common configuration in busy locations on high speed lines is a pair of island platforms, with slower trains diverging from the main line (or using a separate level on the railway's right-of-way) so that the main line tracks remain straight. High-speed trains can therefore pass straight through the station, while slow trains pass around the platforms (such as at Kent House in London). This arrangement also allows the station to serve as a point where slow trains can be passed by faster trains. A variation at some stations is to have the slow and fast pairs of tracks each served by island platforms (as is common on the New York City Subway; the Broad Street Line
Broad Street Line
of Philadelphia; and the Chicago Transit Authority's Red and Purple lines.) A rarer layout, present at Mets-Willets Point on the IRT Flushing Line, 34th Street – Penn Station on the IRT Seventh Avenue Line
IRT Seventh Avenue Line
and 34th Street – Penn Station on the IND Eighth Avenue Line
IND Eighth Avenue Line
of the New York City Subway, uses two side platforms for local services with an island in between for express services. The purpose of this atypical design was to reduce unnecessary passenger congestion at a station with a high volume of passengers. Since the IRT Seventh Avenue Line
IRT Seventh Avenue Line
and IND Eighth Avenue Line have adjacent express stations at 42nd Street, passengers can make their transfers from local to express trains there, leaving more space available for passengers utilizing intercity rail at Pennsylvania Station. The Willets Point Boulevard station was renovated to accommodate the high volume of passengers coming to the 1939 World's Fair. Examples[edit] Many of the stations on the Great Central Railway
Great Central Railway
(now almost entirely closed) were constructed in this form. This was because the line was planned to connect to a Channel Tunnel. If this happened, the lines would need to be compatible with continental loading gauge, and this would mean it would be easy to change the line to a larger gauge, by moving the track away from the platform to allow the wider bodied continental rolling stock to pass freely while leaving the platform area untouched. Island platforms are a very normal sight on Indian railway stations. Almost all railway stations in India consist of island platforms. In Toronto, 29 subway stations use island platforms (a few in the newer stations on the Bloor–Danforth line, a few on the Yonge–University line
Yonge–University line
and all of the Sheppard line). In Sydney, on the Eastern Suburbs Railway
Eastern Suburbs Railway
and the Epping Chatswood Railway, the twin tunnels are widely spaced and the tracks can remain at a constant track centres while still leaving room for the island platforms. A slight disadvantage is that crossovers have to be rather long. In Edmonton, all 18 LRT stations on the Capital Line
Capital Line
and Metro Line use island platforms. The Valley Line under construction, utilizes the new low-floor LRT technology, but will only use island platforms on one of the twelve stops along the line. In southern New Jersey
New Jersey
and Philadelphia, PATCO uses island platforms in all of its 13 stations, to facilitate one-person train operation. Most elevated stations in Singapore's Mass Rapid Transit (MRT) system use island platforms. The exception is Dover MRT Station, which uses side platforms as it is built on an existing rail line, also known as an infill station. Braddell adopts a side-platform-layout due to lack of space to the north of the tunnels. The planned Canberra MRT Station will also use side platforms, as it will also be built on an existing rail line, while Gul Circle use a stacked side platform configuration. Unused sides of island platforms[edit] Sometimes when the track on one side of the platform is unused by passenger trains, that side may be fenced off. Examples include Hurlstone Park and Lewisham. In New York City's subway system, unused sides can be found at Bowling Green as well as every express station without express service, such as Pelham Parkway. In Jersey City, the Newport PATH station has the same configuration as Bowling Green—one side platform and one island platform. On the Tokyo Metro, the Ginza Line
Ginza Line
has a side platform and an island platform at Nihombashi. Likewise, the Namba and Minami-morimachi stations on the Osaka Municipal Subway
Osaka Municipal Subway
have similar configurations. Some stations of the Glasgow Subway
Glasgow Subway
have one island platform and one side platform (Hillhead, Buchanan Street, and Ibrox). In Wellington, New Zealand, unused sides can be found at two stations on the Hutt Valley Line: Waterloo and Petone. Waterloo's island platform was reconfigured to be the down side platform when the station was extensively rebuilt in the late 1980s, with the unused side now facing onto a bus bay. Petone's island platform served the up main line and the suburban loop line until the suburban loop was lifted in the early 1990s. The unused platform now faces onto the station's park-and-ride carpark. Gallery[edit]

Ashton-under-Lyne station, an island platformed station in England.

Island platform
Island platform
tram stop at Winson Green Outer Circle on the Midland Metro, in England.

Navy Yard – Ballpark station on the Washington Metro
Washington Metro
Green Line after a baseball game at Nationals Park.

Island platform
Island platform
at Bowling Green station in New York City with one side fenced off.

Aboveground island platform at Roxbury Crossing station on Boston's Orange Line subway system.

Island Platform at Grafton Station on the Western Line of Auckland's suburban rail network.

Yau Ma Tei Station, an island platformed station in Hong Kong.

Moody Centre station, an island platformed station in Metro Vancouver.

Yorkdale (TTC), one of 29 station in the Toronto
Toronto
system with centre platforms.

Taft Avenue MRT Station, one of the few island platforms in the Manila Metro Rail Transit System Line 3

Corona LRT Station
Corona LRT Station
is an island platformed station in Edmonton.

See also[edit]

Side platform

References[edit]

Wikimedia Commons has media related to Island platforms.

Railway Technical Web Pages

v t e

Railway track
Railway track
layouts

Running lines

Single track Passing loop Double track Quadruple track Crossover

Rail sidings

Balloon loop Headshunt Refuge siding Rail yard Classification yard

Junctions

Flying junction Level junction Double junction Facing and trailing Grand union Wye Switch / turnout / points Swingnose crossing Level crossing

Stations

Railway platform Side platform Island platform Bay platform Split platform Terminal station Balloon loop Spanish solution Cross-platform interchange Interchange station

Hillclimbing

Horseshoe curve Zig Zag / Switchback Spiral

Track geometry

Track gauge Ruling gradient Minimum curve radius Ca

.