Island platform

Beecroft railway stationin Sydney, Australia, is an island-platform station in the middle of areverse curve.
This platform is accessed by anunderpass.

Anisland platform(alsocenter platform(American English) orcentre platform(British English)) is a station layout arrangement where a singleplatformis positioned between twotrackswithin arailway station,tram stoportransitway interchange.Island platforms are sometimes used between the opposite-direction tracks on twin-track route stations as they are cheaper and occupy less area than other arrangements. They are also useful within larger stations, where local and express services for the same direction of travel can be accessed from opposite sides of the same platform instead ofside platformson either side of the tracks, simplifying and speeding transfers between the two tracks.

The historical use of island platforms depends greatly upon the location. In the United Kingdom the use of island platforms on twin-track routes is relatively common when the railway line is in acuttingor raised on anembankment,as this makes it easier to provide access to the platform without walking across the tracks.

Advantages and tradeoffs

Island platforms are necessary for any station with many through platforms. There are also advantages to building small two-track stations with a single island platform instead of two side platforms. Island platforms allow facilities such as shops, toilets and waiting rooms to be shared between both tracks rather than being duplicated or present only on one side. An island platform makes it easier for disabled travellers to change services between tracks or access facilities. If the tracks are above or below the entrance level, the station needs only one staircase and (if disabled accessibility is necessary) one elevator or ramp to allow access to the platforms. If the tracks are at the same level as the entrance, this instead creates a disadvantage; a side platform arrangement allows one platform to be adjacent to the entrance, whereas an island platform arrangement requires both tracks to be accessed by a bridge or underpass.

If an island platform is not wide enough to cope with passenger numbers, typically as they increase, overcrowding can risk people being pushed onto the tracks. In some cases entry to the station is restricted at busier times to reduce risk.Examples of stations where a narrow island platform has caused safety issues includeClapham CommonandAngel(rebuilt in 1992) on theLondon Underground,Union(rebuilt in 2014) on theToronto subway,andUmedaon theOsaka Municipal Subway.

An island platform requires the tracks to diverge around the centre platform, and extra width is required along the right-of-way on each approach to the station, especially on high-speed lines. Track centres vary for rail systems throughout the world but are normally 3 to 5 metres (9 ft 10 in to 16 ft 5 in). If the island platform is 6 metres (19 ft 8 in) wide, the tracks must slew out by the same distance. While this requirement is not a problem on a new line under construction, it makes building a new station on an existing line impossible without altering the tracks. A single island platform also 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 stationon theLondon Underground'sNorthern line

Fast and slow tracks
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'sright-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 atKent HouseinLondon). 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 theNew York City Subway;theBroad Street LineofPhiladelphia;and theChicago Transit Authority'sRedandPurplelines).

TheMets-Willets Pointstation on theNYC Subway'sIRT Flushing Line (7 Train),showing its island platform sandwiched between its two side platforms.

A rarer layout, present atMets-Willets Pointon theIRT Flushing Line,34th Street – Penn Stationon theIRT Seventh Avenue Lineand34th Street – Penn Stationon theIND Eighth Avenue Lineof theNew 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 theIRT Seventh Avenue LineandIND Eighth Avenue Linehave 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 atPennsylvania Station.TheWillets Point Boulevardstation was renovated to accommodate the high volume of passengers coming to the1939 World's Fair.

Examples

Many of the stations on theGreat Central RailwayinEngland(now almost entirely closed) were constructed in this form. This was because the line was planned to connect to aChannel Tunnel.If this happened, the lines would need to be compatible with continentalloading 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.

Australia

InSydney,on theEastern Suburbs Railwayand theEpping 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 thatcrossovershave to be rather long. Examples inMelbourneincludeWest Footscray,Middle Footscray,AlbionandTottenhamon theSunbury line,Kananookon theFrankston Line,Aircraft,Williams LandingandHoppers Crossingon theWerribee Line,Ardeer,Caroline Springson theBallaarat Line,Glen Iris,Holmesglen,JordanvilleandSyndalon theGlen Waverley Line,andWatsoniaandHeidelbergon theHurstbridge line.

Canada

InToronto,29 subway stations use island platforms (a few in the newer stations on theBloor–Danforth line,a few on theYonge–University lineand all of theSheppard line).

InEdmonton,all 18 LRT stations on theCapital LineandMetro Lineused island platforms untilNAIT/Blatchford Market stationopened in 2024, the only station with side platforms as of 2024. TheValley Line Southeastuses low-floor LRT technology, but uses island platforms on only one of the 12 stops,Mill Woods.

Singapore

Almost all of the elevated stations inSingapore'sMass Rapid Transit(MRT) system use island platforms. The exceptions areDover MRT stationandCanberra MRT station,which use side platforms as they are built on an existing rail line, also known as aninfill station.Gul Circleuses a stacked island platform configuration. The same follows for underground stations, with the exception beingBraddell MRT station,Bishan MRT station,Ang Mo Kio MRT station,and a few stations on theDowntown line(Stevens,Downtown,Telok Ayer,ChinatownandMacPherson) and theThomson-East Coast line(Napier,Maxwell,Shenton WayandMarina Bay)

United States

In southernNew JerseyandPhiladelphia,PATCOuses island platforms in all of its 13 stations, to facilitateone-person train operation.TheNYC Subway'sSecond Avenue Subwayfeatures island platforms at all stations.Many other stations in the system have the same layout.

Unused sides of island platforms

Sometimes when the track on one side of the platform is unused by passenger trains, that side may be fenced off. Examples includeHurlstone Park,Lewisham, SydneyandYeronga, Brisbane.

In New York City'ssubway system,unused sides are located atBowling Greenas well as every express station without express service, such asPelham Parkwayon the IRT Dyre Avenue line. In Jersey City, theNewportPATHstation has the same configuration as Bowling Green—one side platform and one island platform.

On theTokyo Metro,theGinza Linehas a side platform and an island platform atNihombashi.Likewise, theNambaandMinami-morimachistations on theOsaka Metrohave similar configurations. On JR East, theYokosuka Lineplatforms atMusashi-Kosugifeature a similar setup following a new side platform opening in December 2022.

Some stations of theGlasgow Subwayhave one island platform and one side platform (Hillhead,Buchanan Street,andIbrox).

InWellington,New Zealand, unused sides can be found at two stations on theHutt Valley Line:WaterlooandPetone.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

• Island platforms around the world
• 
  Ashton-under-Lyne station,an island-platformed station inEngland
• 
  Island platformtram stopatWinson Green Outer Circleon theWest Midlands Metro,in England
• 
  Navy Yard–Ballpark stationon theWashington MetroGreen Lineafter a baseball game atNationals Park
• 
  Island platform atBowling Green stationon theNew York City Subwaywith one side fenced off
• 
  An example of a basic island platform in Japan.Ōto Stationon theNarita Line.
• 
  Taft Avenue station,one of the few island platforms in theManila Metro Rail Transit SystemLine 3
• 
  Nunawading stationon theBelgraveandLilydalelines inMelbourne,Australia.
• 
  Gambir railway stationis an island-platformed railway station inJakarta,Indonesia.

See also

• Platform height
• Railway platform
• Side platform
• Split platform
• Spanish solution

External links

• "Stations".Railway Technical Web Pages.30 May 2007. Archived fromthe originalon 9 June 2007.