Cross Platform Interchange - No Escalator Rides ☹

In a metro system with multiple lines, usually a person transfers from one line to another to reach their destination. A station where one can transfer is called an interchange. In an interchange, normally the lines are stacked one above the other. This means one must use stairs, escalators or lifts to interchange between lines.

A cross-platform Interchange ( CPI ) is a type of interchange, where changing from one line to another means just walking across the same platform and does not require usage of stairs, escalators, or lifts.

When two lines cross each other,  there is a maximum of 8 possible ways to transfer between lines. I will look at some interesting station designs which enable easy cross-platform interchange

Island platforms play an important role in enabling CPI.

Full CPI or Paired stacked-island cross-platform

This supports all possible interchange movements. This requires two stations. Each Station has two island platforms stacked one above the other.

This supports all possible interchange movements. This requires two stations. Each Station has two island platforms stacked one above the other.  

If you notice, it is possible to continue in any direction on the other line with this set of interchanges, just by walking across the platform at either station.

City Hall and Raffles Place which serve the red and green lines on the Singapore MRT ( Mass Rapid Transit )are an example of this.

First this is like “uh! They have two platform Interchanges in row.” But this is not the case. Basically, if you want to continue in the same direction, you transfer at one station and if you want to head in a different direction, you transfer at another.

The track layout is arranged in a way that there are two levels and train swaps levels when going from one station to another. This is also how direction changing is possible.  

Single Station Same Level cross-platform interchange

In this type, there are three island platforms on the same station, and they support 6 of the 8 possible transfers. It is obvious that that the trains have doors on both sides to make use of this approach.

This is the most common CPI that is used across the world. An example of this is the Fulton Street Station on the New York City Subway

 

Another example of this can be found in London Underground, where there are two Island platforms in a single station, instead of three.  This reduces the number of CPIs supported to only 4 of the possible 8 transfers.

Single Station Stacked Platform Interchange

In this case, there are two island platforms, stacked one above the other in a single station. This arrangement supports 4 of the possible 8 transfers.  Lai King Station on Hong Kong MTR (Mass Transit Railway, not Mavalli Tiffin Room) is an example of this.

In this case,  the dominant direction of each line is present  in each of the island platforms. This allows people to transfer to and from dominant direction easily.  

 Another example of this is Taipei metro, which has three stations with Stacked Island platforms on each of them. This serves three lines, namely Red, Green and Yellow lines.

 

Please note there there are around 66 cities with CPIs in the world of which I’ve covered only a few and of the 66 CPIs 14 are in China. Not too surprising for me. ( 41 of 204 Metro systems are in China ) anyway, see you later.

Unfortunately, none of them are in India. Before you start questioning me,  the mainline railway platforms in India,  which have two tracks in between two island platforms are considered as CPI.

Hopefully this is the last post, where I bore your about metro trains.

Thank-you