With distance, you would probably also need to determine the direction... will it be 'like a train' and follow a track (or path) ?
If it is going to be like a train, you could always have the locomotive and then pin your cars, one to the other forming a chain for your train.
Then have your train move by xx pixels initially, say 2, then click and it moves by 4, then click and it moves by 6... you could set up a variable for this and use whichever mouse click (or touch) event that would suit your needs... meaning, can the player click anywhere, on a button or throttle control or click directly on the locomotive...
First, get your locomotive moving like you want and then add the cars... At least that is how I would approach it... One step at a time...
There are several ways this could be approached, all depending on your wants and need but maybe this will help a little...
Try searching thru the tutorials using different keywords... You probably won't find one to give you exactly what you need but you should be able to pick up enough bits and pieces to get your train moving in the right direction...