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铁路月台 is a section of pathway, alongside rail tracks at a train station, metro station or tram stop, at which passengers may board or alight from trains or trams. Almost all stations for rail transport have some form of platforms, with larger stations having multiple platforms. The term platform is most commonly used, in British usage, for designated areas where trains stop (Platform 1, 2, 3, etc.; the American equivalent is track). Technically speaking, the term platform actually refers to physical continuous sections of platform area. So such a physical platform may contain several "designated" platforms.
The term railway platform can also mean any type of freight platform beside a rail siding for loading/unloading freight to/from rail cars.
Characteristics
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A most basic form of platform consists of an area at the same level as the track, usually resulting in a fairly large height difference between the 'platform' and the train floor. This would often not be considered a true platform. The more traditional platform is situated at an elevated level relative to the track, but often lower than the train floor, although ideally the platform should be at the same level as the train floor. Occasionally the platform is at a higher level than the train floor. This may be the case when a train with a low floor level serves a station built for trains with a higher floor level, for example at the Dutch stations of the DB Regionalbahn Westfalen (see Enschede). Likewise, on the London Underground some stations are served by both District Line and Piccadilly Line trains, and the Piccadilly trains have lower floors.
A tram stop is often in the middle of the street; usually it has as a platform a refuge area of a similar height to that of the sidewalk (eg. 10 cm), and sometimes has no platform at all. The latter requires extra care for the boarding and unboarding passengers and for the other traffic to avoid accidents. Both types of tram stops can be seen in the tram network of Melbourne. Sometimes a tram stop is served by ordinary trams (with rather low floors) as well as metro-like light rail vehicles with higher floors, and the tram stop is provided with a dual height platform. An example can be found in Amstelveen, Netherlands. Similarly a train station may be served by heavy-rail and light-rail vehicles (with lower floors) and also have a dual height platform. This applies for example on the RijnGouweLijn, Netherlands.
Facilities
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Part of the station facilities are usually on the platforms. Where the platforms are not situated within a station building, often some form of shelter or waiting room is provided. The protection offered by such varies greatly – some being little more than a roof with open sides, others being a closed room with heating or air-conditioning (the roof also provides shade; this may be a disadvantage in colder climates). Also there may be benches, lighting, garbage boxes and static timetables or dynamic displays with information about the next train, delays, etc. There are often loudspeakers as part of a public address system. The PA system is often found where dynamic timetables or electronic displays are not present. A variety of information is presented, usually pertaining to departures, but often arrivals also. This concerns destinations and times (for all trains, or only the more important long-distance trains), delays, cancellations, platform changes, changes in routes and destinations, the fact that for a train a supplemental fee or a reservation is required, etc.
Types of platform
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Platform types include the bay platform, through platform, island platform, and the side platform. A bay platform is one at which the tracks terminate, i.e. a dead-end or siding. Trains serving a bay platform must reverse in or out. A through platform, conversely, is the more usual type of platform, located alongside tracks where the train may simply pull into the platform from one end, and leave passing the other end. Finally, an island platform has designated through platforms on both sides; it may be indented on one or both ends, with bay platforms. For passengers to reach an island platform, there may be a bridge, a tunnel, or a level crossing. The climb up to the bridge or down to the tunnel may use stairs, ramps, escalators, lifts, or a combination of the above.
Some stations, such as Limerick Junction, in County Tipperary, Ireland, consist solely of an island platform hosting all platform numbers, as well as the station building entirely surrounded by track.
Usually "platform" numbering is actually a numbering of the boarding/alightment areas in the station (hence one island platform, for example, may have several numbered "platforms"). In some cases, tracks without platform access, used for through traffic, also have a number.
Platform safety
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Platforms usually have some form of warnings or measures to keep passengers away from the tracks and moving trains. The simplest measure is markings near the edge of the platform to demarkate the distance back from the platform edge that passengers should remain. Often a special tiled surface is used as well as a painted line, to help blind people using a walking aid, and aid in preventing wheelchairs from accidentally rolling too near the platform edge. A dangerous practice that sometimes occurs is sitting on the edge of the platform, which requires being fast enough in withdrawing the legs when a train arrives.
In high-speed rail passing trains are a significant safety problem, as the safe distance from the platform edge increases with the speed of the passing train. Several countries have laws that prohibit trains passing platforms above certain speeds (usually 200 km/h (120 mph)). For stations on high-speed lines this leaves two alternatives unless all trains stop there: Either a speed limit for passing trains is introduced or the station has to be rebuilt to include tracks that do not pass platforms.
Some metro stations have platform screen doors between the platforms and the tracks. They provide more safety; also they allow the heating or air conditioning on the station and the ventilation in the tunnel to be separated, thus being more efficient and effective. They have been installed in most stations of the Singapore MRT and the Hong Kong MTR, as shown in the photos below, and the newer stations forming the Jubilee Line Extension in London.
Curvature
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Ideally platforms should be straight or slightly convex, so that the guard can see the whole train as he prepares to close the doors. Platforms that have great curvature have blind spots that create a safety hazard. Mirrors or closed-circuit cameras may be used in these cases to view the whole platform. Also passenger carriages are straight, and so doors will not always open directly onto a curved platform – often a gap is present. (Usually such platforms will have warning signs, possibly auditory, such as "Mind the gap"). In some cases, sections within the platform may be movable, so as to cover any gap; moving away again to allow the train to leave.
Length
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The longest railway platform in the world (1,072 metres, or 3,538 feet) is at Kharagpur, West Bengal. The longest in the UK is at Gloucester railway station. The longest in Australia is at Flinders Street Station, Melbourne. Though spread over 4 stations, the longest platform in the US on a metro line is on the Red Line in the State Street subway in Chicago, Illinois.
As part of gauge conversion works, Indian Railways in 2006 sought funds to lengthen 100 stations to take passenger trains with 24 carriages. [1]