I came across a train shop out of NJ, All Aboard Train Shoppe, that has a nice online reference to Lionel products. Their website has a listing of Lionel train sets by year from 1945 to 1969. So I looked up my original set from 1955, and it appears I still have all the original cars. Still have the 1033 transformer for it as well.
That's the set just behind the saw mill. Caboose, crane, gondola, tender and 1615 engine.