Don't worry, the final thing is going to be much longer, but with only a couple new cars as the whole thing is essentially tiled, so we can re-use the same kind of car, say a SAM car, over again.
I'm tired and have school tomorrow, so I have to keep this brief:
The idea behind the train mission is to have more arcade style combat than the normal gameplay, with turrets popping up and having to be destroyed similar to the ships in 1942 and the like. There's also an important EMOTION element that we may employ, but I'm not sure if it's final yet.
Sorry for the brevity, but I'm about to collapse, practically.