HAVE TWO ENGINES THAT WILL ONLY RUN IN REVERSE

[TRAIN185]

I recently purchase some trains from someone who has not run the trains in years.  There are two William engines.  one F7 and one steamer (a brass one).  Both will run in reverse only.  I have tried moving the switch on the bottom---no change.  Any ideas as to what is going on hers.  (Running them on an MTH Z_4000).

[trainyardjp]

JP, of Acton MA, USA writes:

Remove the shells of the locos, look at the internal wiring and the electronics. Check for any loose or disconnected wires, and check for any problems with the electronics.
Williams by Bachmann does sell replacement electronic reverse boards (E-Units), so if the problem is with the reverse board, then you might need to replace it.

Hope this helps.
-JP