Here are a few free patterns. Two have only only have one train car.
http://www.lynbrown.com/do-you-see-c...-santas-train/
http://www.stallingsglass.com/store/...at=1022&page=3
http://www.craftville.com/free-craft...Other/train_a4
There is a free pattern of a whole train by a fabric manufacturer, but I can't remember who. I thought I had the pattern, but it may be named after a fabric line and not called train or something similar.