I once saw another video by nimo 5 that a camera was put at the back of a train. The train later divided into 2 and headed for different destinations. nimo 5 filmed the scene from the back of train A heading to direction A. But he has another camera that fellow him to the journey heading to direction B in train B. If you know what I mean :D
Either that or the two chaps using the other two were well concealed behind posts. I looked hard but couldn't see them or the cameras. There's a chap in the US using at least four. Not so difficult now with card and hard drive recorders. A total pain with tape. Great clip, well thought out and put together.