The 'cutting-edge' safety feature in modern subways consists of transparent doors that separate rail tracks from platforms. Train doors and platform doors are aligned and open simultaneously after the train has stopped.
Subway systems with platform screen doors (also called PSD, platform edge doors, or PED) or half-high platform gate doors (PGD) in some or all of their stations:
Preventing people from falling or jumping on the tracks,
allowing trains to enter the stations at higher speed,
reducing draught and air pressure caused by trains,
letting platforms be quieter and cleaner,
in hot climate, allowing the stations to be air-conditioned at lower cost,
preventing trash wafting into the tunnels and thus reducing the risk of track fires.
So PSDs can increase passenger comfort and average train speed, though PSDs usually need more time to open and close than ordinary doors. In an emergency they can be opened manually from both sides. Video of Hong Kong's Tung Chun station PSDs.
Less common are chest-high or waist-high platform gate doors like those on Hong Kong's MTR Disneyland Resort Line and Tokyo's Disneyland Monorail as well as in some stations in Paris and Taipei.
Singapore MRT was the first subway system to introduce real PSDs in 1987, with its inauguration. PSDs are often being built in new subway stations but can also be retrofitted in existing stations. In addition to the subway systems listed above, platform screen doors are found in most people movers (e.g. at airports) and monorails.
Saint Petersburg has ten stations with a unique feature: platform steel doors, not screen doors (see video). The stations were built between 1961 and 1972. Contrary to common belief, the reason for the introduction of steel doors was not to prevent flooding. The reason was to lower the costs of station construction when using tunnel boring machines. When tunnel boring machines (TBM) are used, station vaults normally are constructed to have a wider profile than the TBM to host part of the platform, which requires expensive manual digging. But those Saint Petersburg stations each consist of two tunnels with the narrow profile of the TBM and a larger station vault in between. The walls between the track tunnels and the vault carry all the weight of the ceiling and allow only for narrow openings. These openings had to be covered with sliding doors for safety reasons. This makes Saint Petersburg actually the world's first metro with platform doors ("horizontal elevator"), though they are not made of glass.
London is planning to install platform screen doors on four lines, together with automated train operation: on Bakerloo, Central, Piccadilly, and Waterloo & City lines. The future metros of Pune and Riyadh will be equipped with PSDs. Munich will retrofit metro stations with PSDs from 2023.
Copenhagen
Hong Kong
Sunny Bay station. Hong Kong has platform screen doors in all underground stations. However, the Disneyland Resort Line is equipped with chest-high platform gate doors (PGDs).
Lille
Porte de Valenciennes elevated station.
London
Canary Wharf station, Jubilee Line Extension.
London
Canary Wharf station, Jubilee Line Extension.
Paris
Saint-Lazare station, line 14 (Météor).
Photos by Mike Rohde. Page updated 3 Aug 2019 - data updated 2 Jul 2021.
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