Interesting idea, but there are some issues: - Many modern trains, including the TGV, are not designed to be separated during normal operation. - If you add a

Interesting idea, but there are some issues: - Many modern trains, including the TGV, are not designed to be separated during normal operation. - If you add a car to the front, the train driver can't see anything. If you remove it, you remove their workplace. In a push-pull train, the same applies to the back. A foldable cab like the IC3[1] has might be a solution, but it's far from aerodynamic. - Uncoupling the last cab instead of stopping has been done in the past. But coupling one without stopping sounds very hard. - Instead of one train, you now have three: The car being decoupled, the new one, and the rest. Generally, that means the station needs a higher capacity. Not sure if that's the case here though. Normally what limits a station's capacity is that you can't have two trains using the same track, but that doesn't really apply when you want to couple/uncouple them. [1] https://en.m.wikipedia.org/wiki/IC3 https://en.m.wikipedia.org/wiki/IC3