Lionel 8632 Steam Engine won’t run

I have a Lionel 8632 Steam Engine, purchased used with a guarantee that it worked well when stored about a century ago.  It was the usual dirty, dusty stored in a jumble with many  other pieces of rusty track etc.  A little jerky movement when I put it on my test track.  Disassembled, cleaned, oiled, greased but no change.  Found that the control board, or is it called the electronic e-unit, was hot to touch.  The red and black wires were stuck together where they crossed over each other.  Their coverings were melted but I couldn’t see where there was any exposed wire.  The plastic part holding the control board has a melted section where the black and red wires poke through the control board. When I tried running the motor without the body on it the control board started to smoke.  I cleaned the back side of the control board. So the question is how do I diagnose the problem, can it be salvaged or is it toast?  I tried to find a new/used control board without success.  Is there some other way to make it run?  The little motor runs when attached to a DC transformer