wolfiejr,
I believe you have the Lionel #218 Alco locomotive in Santa Fe livery, one of the postwar "200" series of which there were quite a few with many similarities but also a few differences. Try this link for starters:
http://pictures.olsenstoy.com/200alco.htm
Be sure to study all of the pages, as your version is one of the later ones.
You can purchase many of the parts from Olsen's, as well as many other sources.