Except the innermost (or outermost) platform is a platform number, others are two numbers of a platform surface. If a station has two basic platforms and three intermediate platforms, its serial number is A 1/B 1 (platform 1/ basic platform).

The numbers of the three intermediate platforms are: A2/B2 (platform 2) A3/B3 (platform 3); A4/B4 (platform 4) A5/B5 (platform 5); A6/B6 (platform 6); A7/B7 (platform 7); A8/B (Platform 8/Basic Platform). To sum up, it can be seen that 1 is a platform, 2/3 is a platform, 4/5 is a platform, 6/7 is a platform, and 8 is a platform.

If the waiting room is located on one side of the line, then 8/9 is a platform. More stops and so on. Tickets at big stations are generally marked with ticket gates. For example, if the ticket says that you will check in from A7/B7, the train will stop on the line near the waiting room of platform 4.

There are many reasons for using a dual island platform:

1. This is the trunk line station, but the train parking lot depot is here, so there should be two tracks, one for dropping off passengers and the other for returning to the warehouse, so as not to delay the normal operation. (such as Beijing Maquanying Station and Bagou Station)

This station is a transfer station on the same platform, with two tracks on both sides of a line and two tracks in the middle. (Beijing National Library Station, Guogongzhuang Station, Zhuxinzhuang Station, Beijing West Railway Station; Hong Kong Prince Station, North Point Station, Mong Kok Station, Lai King Station, etc. )

There are big station express trains and overpasses on this line. (such as Xinhua Street Station of Beijing Metro Line 6).