Recently I purchased brand new from a train dealer Thomas with sound and Henry the Green engine.  Both engines run well. But whenever Thomas goes over a turnout, going straight or turning, he derails.  I bought this for when my grandchildren come they can run them on my layout. They love the train and the sounds but are very frustrated as the engine derails so frequently. Henry the Green engine, which is larger and has a tender, does not derail. I have eight other engines and none of them derail at the turnouts. Would any of you have a suggestion to stop this from happening?