If that were the case the locomotive would atleast try and move, but it does nothing.  No movement of the drive shafts or the gearbox.  I'm leaning more towards the sound decoder.

HO scale

sorry typo error it,s a climax.

I purchased a 3-Trk Shay back in June of 2015, up until now has been running better than I expected, now it sits on the track and sounds like it is running while sitting still,  it started doing in sporatically now it does nothing.  Just sits on the track and sounds like it should be moving.