How can I move a group along a path? I created a very simple railroad using an array-modifier followed by an curve-modifier, after that I wanted to run a train on the railroad. The Locomotive is consisting of several grouped objects which can be moved as a whole.



When a add another curve modifier to the groups parent all other grouped items stay in their previous location.

How could the group be moved along the curve?
It seems you have added a curve modifier which will 'bend' the object along the curve.

What you want to do, is to go to the Constraints-panel and add a Follow Path constraint to the parent. From there you can tick Follow Curve and press Animate Path to make the train drive along the rail.