Although the station platform only allows room for a three-car trainset, when the station was first opened a six-car trainset was used on the line. In this case, only the first three train cars' doors opened at this station (selective door operation). It was not until 22 July 2006 that a dedicated three-car trainset began service on the line. https://en.wikipedia.org/wiki/Xiaobitan_metro_station
https://en.wikipedia.org/wiki/Selective_Door_Operation (SDO)
https://en.wikipedia.org/wiki/Taipei_Metro#Platforms
https://en.wikipedia.org/wiki/Multiple_unit
SDO is such a great way to add a couple of cars without having to extend the platform until its absolutely necessary.
https://www.youtube.com/watch?v=TNtT0U-5zME ber
https://www.youtube.com/watch?v=0epKxaeCCHE sth
https://jfdatalinks.blogspot.com/search?q=Selective+Door+Operation
