Does the rail or train have any special needs? Because if they don't, I believe you could use the "Tween" behavior or the "Move To" behavior. Both behaviors have triggers that help you make changes on the path.
If you still find trouble using the behaviors, I could send you a small sample, but if you try to use the behaviors yourself, it would be immensily more helpful to you as a developer.
Feel free to ask for help at any time. Cheers.