Hi all, I’m driving the class 377 8-car unit on the East Coast mainline. However, some stations have too short platforms. The last car is not at the platform... I wanted to split the train upon departure to make it a 4-car, but I couldn’t figure out how to do that. The cabin has a ‘couple’ button, nothing happens when I press it. How can I split/join a train? Best to all of you!