Here's a train set that will inspire many young and perhaps even a few older imaginations. 

 

At first glance the train set may seem like a lot of work. But don't be fooled. You'll discover that the train is designed around a simplified common chassis system, where all the cars except the locomotive share identical undercarriages. Once you've set up your table saw you can easily knock off as many undercarriage parts as required by the number of cars you plan to build.