I'm just speculating here, but isn't it possible that the second launch can separate the track into two blocks as well? Let's say train 2 doesn't make it over the final hill and rolls back, while train 1 is still somewhere in the first block. They will both end up stopped in the launch section, where they can be evacuated, launched separately, whatever. I'm not sure if something like that has been done before, but it would theoretically work, no?