3 things I just want to say 
Firstly, unfortunately, I don’t actually think this set-up would be very easy to use in a moving train… I’ve used the co-ord system and position values in XPressionist… I’d need to make a more complicated scrip to make it moveable. That and I’m no modeller, I don’t think I’d do a very good job at making the train in the first place 
In case anyone wondered why I don’t post the project, I just like to see how many people are interested, and I know that if I post it some people won’t tell me.
So it’s just nice to know.
And for anyone who does see the final project, one thing to bare in mind is that for setups like this, where I’ve needed to use Xpressionist a little, NEVER use constraints… Xp really doesn’t play nice as soon as you add even a single one into the mix. Try to do everything constraint related via Xp. This also means that you can use looped constraints 