Have you done it?
I have an older Williams BL2 in the Missouri Pacific scheme that I have always like, (MTH never painted their BL2 in Mopac colors).
I recently bought a MTH SD24 with PS3 very cheap.
I would like to know if the motors mount the same in the trucks? I would transplant all the electronics out of the MTH into the Williams BL2.
The key point being that the motors need speed tapes and reader to operate in command mode.
Just an idea I was thinking about, haven't had a chance to look to see how the Williams trucks and motors screw together.
Dan