A cross-platform interchange is a type of interchange between different lines at a metro (or other railway) station. The term originates with the London Underground; such layouts exist in other networks but are not commonly so named. In the United States and Canada, it is often referred to as a cross-platform transfer.
This configuration occurs at a station with island platforms, with a single platform in between the tracks allocated to two directions of travel, or two side platforms between the tracks, connected by level corridors. The benefit of this design is that passengers do not need to use stairs to another platform level for transfer. A cross-platform interchange arrangement may be costly to build due to the complexity of rail alignment, especially if the railway designers also arrange the track with flyovers (which is typically done to increase efficiency).
A typical bidirectional cross-platform interchange configuration consists of two outbound directions of two different lines sharing an island platform, and the respective return directions of both lines sharing a different island platform in the same station complex. Less common is a cross-platform interchange to transfer onto a continuation of same single line served by that station; examples of such interchanges include and in the United Kingdom, Pittsburg/Bay Point on the BART in California, and Estadio Metropolitano, Puerta de Arganda and Tres Olivos on the Madrid Metro.
Types
Between different lines Common cross-platform interchanges allow passengers to change trains without changing to another platform. This applies at places where trains of different directions meet in minor and major hubs, but this arrangement is only found at some interchange stations in metro and other rail networks worldwide.
Between different train categories of the same line Some railway lines, usually in more congested areas, also offer cross-platform interchanges between different categories of trains, for example between express and stopping ("local") trains. For instance, this kind of interchange is used at many European railway minor hubs to connect fast trains to local feeder services, as well as surface sections of suburban lines like the RER E in Paris or the Metro North Hudson Line in New York State. However, local–express interchanges are found in only a few metro networks, such as Chicago, Chengdu, London (as in the case of Stratford discussed below), New York City, and Philadelphia. The New York City Subway system has numerous stations facilitating cross-platform transfers between local and express trains, typically using pairs of island platforms, each serving express trains on one side, and local trains on the other side, with both alternatives headed in the same direction.
As express and stopping trains usually head for different directions, cross-platform interchange between different train categories (e.g. interchanges between metros and railways) is commonly combined with cross-platform interchanges between different lines.
Some stations offer cross-platform transfers between different modes, such as tram and bus, such as at Madeleine station in Charleroi, where two island platforms sit between a central bus lane and tram line on the outside. Similarly, light rail–bus connections can be found at Juniors Kingsford and Haymarket light rail stations in Sydney.
Continuation of travel in different trains
Ormskirk railway station in Lancashire, United Kingdom, was a double-track railway until 1970, when it was converted into single-track railway with the track split in the centre by buffer stops placed back-to-back. The two ends of the single platform terminate different routes, and interchange for through service is by walking along the platform.
Another peculiar configuration exists at Pittsburg/Bay Point station on the BART system in the San Francisco Bay area, California, United States. Mainline BART trains terminate at that station, but onward service is available via an eBART diesel multiple unit (DMU) train. At this station, eBART trains are only accessible through a cross-platform transfer at a dedicated platform east of the main station platform. Despite this transfer, the Yellow Line is mapped and signed as one continuous route.
Konggangxinchengjiangning station of Nanjing Metro, China is also a cross-platform terminal station for both Line S1 and S7, with a single island platform and crossovers set at both ends of station, letting trains of both lines to switch back.
Zhongli railway station in Taoyuan, Taiwan has a proposed cross-platform terminal plan for both Taoyuan Airport MRT and Green line of Taoyuan Metro. The station layout will be composed of two island platform, between which a connecting zone set to integrated the two into a single "large platform". Buffer stops will also be placed back-to back between Airport-bound trains and Green Line trains. The scheme is scheduled to complete in 2031.
Service levels of connections
In some, but not all, cases, the trains are coordinated in the timetable.
Noncoordinated In this case, the cross-platform infrastructure offers the possibility of easily changing trains, independently from the waiting time for the second train. In metro systems with short headways, typical waiting time is small, but such a noncoordinated approach could reduce the advantages of stairless cross-platform interchange in railway networks with sparser train traffic.
Coordinated A more-advanced approach involves the coordination of the lines' timetables to reduce the scheduled changing time, either from one line to the other, or ideally bidirectionally, between both trains simultaneously. Coordinated interchange is widely used in Dutch, German, and Swiss railway networks, where trains of different lines meet at the same platforms in numerous hubs all over the country.
Optimised, with connection guarantee Most advanced are coordinated cross-platform interchanges wherein interconnected trains also wait for each other, to "guarantee" scheduled interchanges even in the event of modest delays. To limit schedule disruption propagation throughout the entire network, additional waiting time for trains is usually limited to a certain period of time, depending on general network performance, further connections to be guaranteed, train category, train line, and a balanced consideration of other factors.
In practice, most railways coordinating cross-platform interchanges define a certain waiting time window for each guaranteed interchange. Some railway operators will briefly delay train departure signals to allow imminently arriving passengers time to interchange. For example, the Vienna U-Bahn metro signals train drivers to wait briefly, by operating a special white light signal triggered by the approach of an interchange train on another track.
Example interchanges In most cases, only cross-platform interchanges used for both directions of travel are listed, with some exceptions.
Asia
Bangkok
Siam Station allows for a cross-platform transfer between the Sukhumvit line and the Silom line, both operated by the BTS, for trains heading in the same direction. Eastbound trains use the lower-level island platform, while the westbound trains depart from the upper-level platforms.
Beijing Cross-platform interchanges are offered between Line 9 and Fangshan Line at , Lines 4 and 9 at , Changping Line and Line 8 at , Lines 7 and 9 at Beijing West railway station, and Fangshan Line and Yanfang Line at . In addition, cross-platform interchange is possible at between Line 6 and 8 via level corridors.(Chinese) The Line 5 alighting platform and Yizhuang Line boarding platform at connect perpendicularly in a T-shape, allowing single-direction cross-platform interchange from Line 5 to Yizhuang Line.(Chinese)
Chengdu
Xipu Station in Chengdu provides cross-platform interchange between Line 2 of Chengdu Metro and Chengdu–Dujiangyan Intercity Railway of the national rail transport system. It is the first implementation of cross-platform interchanges between different train categories in China. Metro-only cross-platform interchanges exist between Lines 2 and 4 at Chengdu University of TCM & Sichuan Provincial People's Hospital station, between Lines 5 and 6 at Xibeiqiao station, between Lines 17 and 19 at Jiujiang North station, between Lines 18 and S3 at Futian station and outbound direction interchanges between Lines 3 and 10 at Taipingyuan station.
Chongqing Line 5 and Line 6 of the Chongqing Rail Transit offer a paired cross-platform interchange for passengers transferring among four directions between the two lines at Ranjiaba and Dalongshan stations. Same-direction cross-platform interchanges are also provided at Chongqing West Station between Line 5 and Loop line, Baoshuigang between Line 4 and Line 9, Shangwanlu between Line 10 and Line 9 and Wangjiazhuang between Line 6 (International Expo Branch) and Line 10. Meanwhile, an opposite-direction cross-platform interchange is provided at Jiangbeicheng between Line 6 and Line 9.
Aside from these, Min'an Ave. between Loop line and Line 4 is an exception. Due to the fact that Line 4 only uses one side of the platforms at this station, there formed a half cross-platform interchange.
Dalian The Dalian Metro has a cross platform interchange between Line 1 and Line 12 at Hekou Station.
Delhi The Delhi Metro has 4 cross-platform interchanges in total. These are located at the following stations:- Central Secretariat: Underground interchange between the Yellow Line and Violet Line Yamuna Bank: At-grade interchange between Line 3 (Main line) and Line 4 (Branch line) of the Blue Line Anand Vihar: Elevated interchange between Line 4 (Branch line) of the Blue Line and Pink Line Botanical Garden: Elevated interchange between Line 3 (Main line) of the Blue Line and Magenta Line
Fuzhou Fuzhou Metro's Difengjiang station offers a cross-platform transfer between Line 4 and Line 5 and Liangcuo station between Line 1 and Line 6.
Guangzhou Guangzhou Metro offers three two way cross-platform interchanges by 2016, between Line 2 and Line 3 at Jiahewanggang station, between Line 8 and the Guangfo Line at Shayuan station, between Line 22 and 18 at Panyu Square station, between Line 14 and 21 at Zhenlong station, between Line 11 and 21 at Tianhe Park station, one between both branches of Line 3 at Tiyu Xilu station and between Line 11 and 12 at Chisha Station. At Tiyu Xilu station the northern section of Line 3 terminates at the center track serving both island platforms connecting to the southern section of Line 3 stopping at the outer tracks. In 2016, a same-direction cross platform interchange started operating between the westbound Line 7 and northbound Line 2 trains at Guangzhou South Railway Station. Several cross platform interchanges are under construction. These include: Guangzhou Baiyun Railway Station (Line 12 and 24) and Caihongqiao station (Line 13 and 11).
Hangzhou Hangzhou Metro's East Railway Station and Pengbu station offer paired cross-platform interchange between Line 1 and Line 4 and another paired cross-platform interchange at West Lake Cultural Square and Wulin Square stations between Line 1 and Line 3. Same-direction cross-platform interchange is offered between Line 2 and Line 4 at Qianjiang Road station, Coach Center between Line 1 and Line 9, Zhejiang Chinese Medical University station between Lines 4 and Line 6, Xintiandi Street station between Line 3 and Line 4, Guanyintang station between Line 7 and Line 9, South Xixi Wetland station between Line 3 main line and branch line (Line 14 future), Lvting Road station between Line 3 and Line 16 and West Railway Station between Line 3 and Line 19.
Hong Kong