I tried assembling a locomotive with wheels with ``Hogwarts Express Collector's Edition'' that can completely reproduce Harry Potter's ``Hogwarts Express'' with Lego blocks - GIGAZINE
LUGNET News : ~3813/epicyclic3
LEGO IDEA #3 freewheel mechanism - YouTube
How to build a LEGO FreeWheel - YouTube
Lego Technic - Technic Brick Power - All about Lego Technic building techniques