Use RWTools. If you end up with more or less wagons than you originally had, you should be able to go into the editor and drag the whole train a few yards (or meters if you don't speak Americanese) to where you need it. Sounds like you've not had RWTools for long so trust me, you can use it to change almost anything without the hassle of the editor. Play with it as much as poss before you end up spending the next 6 months doing everything the hard way
