I don't own a Key, although one was here when the MTH casting came back from the foundry, so I could compare shrinkage.
From left - early CLW, Lionel plastic, Overland late brass, and MTH in Nickel Silver. Lionel wins in this group shot. The Lionel now has the Overland trucks and gears; the Overland is an empty shell. MTH can easily be fixed - I plan a repaint in the not so immediate future.