Santa Claus gave me a Broadway Limited for Christmas, a 4-6-4 New York Central. It keeps derailing. I tired to run it on two different sets of track: one was a simple oval of Bachmann EZ track that my wife and I have running through her Christmas village in our living room and the second was on my train table in the basement. The basement track is model power flex track. It doesn't like the curves on either track and constantly derails. What a bummer for such an expensive toy! My cheap engines run just fine on both sets of tracks. What a disappointment! Any words of wisdom???? 
