A railway platform is an area alongside a railway track providing convenient access to trains. Almost all stations have some form of platform, with larger stations having multiple platforms.
The world's longest station platform is at Hubbali Junction in India at . The Appalachian Trail station or Benson station in the United States, at the other extreme, has a platform which is only long enough for a single bench.
Among some United States train conductors the word "platform" has entered usage as a verb meaning "to berth at a station", as in the announcement: "The last two cars of this train will not platform at East Rockaway".
Height relative to trains
The 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 elevated relative to the track but often lower than the train floor, although ideally they should be at the same level. Occasionally the platform is higher than the train floor, where a train with a low floor serves a station built for trains with a high floor, for example at the Dutch stations of the DB Regionalbahn Westfalen (see ). 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, e.g. , and sometimes has no platform. The latter requires extra care by passengers and other traffic to avoid accidents. Both types of tram stops can be seen in the tram networks of Melbourne and Toronto. Sometimes a tram stop is served by ordinary trams with rather low floors and metro-like light rail vehicles with higher floors, and the tram stop has a dual-height platform. A railway station may be served by heavy-rail and light-rail vehicles with lower floors and have a dual- height platform, as on the RijnGouweLijn in the Netherlands.
In all cases the platform must accommodate the loading gauge and conform to the structure gauge of the system.
Types of platform
Platform types include the bay platform, side platform (also called through platform), split platform and island platform. A bay platform is one at which the track terminates, i.e. a dead-end or siding. Trains serving a bay platform must reverse in or out. A side platform is the more usual type, alongside tracks where the train arrives from one end and leaves towards the other. An island platform has through platforms on both sides; it may be indented on one or both ends, with bay platforms. To reach an island platform there may be a bridge, a tunnel, or a level crossing. A variant on the side platform is the spanish solution which has platforms on both sides of a single through track.
Modern station platforms can be constructed from a variety of materials such as glass-reinforced polymer, pre-cast concrete or expanded polystrene, depending on the underlying substructure.
Identification
Most stations have their platforms numbered consecutively from 1; a few stations, including , , King's Cross, , and (in the UK); and Lidcombe, Sydney (Australia), start from 0. At platforms 3 through to 12 are split along their length with odd numbered platforms facing north and east and even facing south and west, with a small signal halfway along the platform. Some, such as , use letters instead of numbers (this is to distinguish the platforms from numbered ones in the adjoining Waterloo main-line station for staff who work at both stations); some, such as Paris-Gare de Lyon, use letters for one group of platforms but numbers for the other.
In the US, and also some European countries such as Sweden, a designated place where a train can arrive is referred to as a "track" (e.g. "The train is arriving on Track 5"). The term "platform" is also used in the US but refers to the structure rather than a designated place for a train arriving. Therefore, an island platform would be described as one platform with two tracks. In some cases, there are numbered tracks which are used only for through traffic and do not have platform access. In other English-speaking countries, "platform" can refer to both the structure or to a designated place for trains arriving (e.g. "The train is arriving at Platform 5"). Therefore, an island platform might have two numbered platforms.