Wliiiams dummy loco question; what does "W/PLUG" mean? I just got ...

I haven't seen that before. Just a guess, maybe a plug on the internal wire harness to add a power upgrade kit or lights.

Not really sure but I think that W/Plug  means "with Plug."  Just a wild guess.

Check this 2006 review of the williams rectifier, maybe the answer?

https://www.trains.com/ctt/new...-rectifier-electric/

Of special note is “the plug.” The Rectifiers had a unique resolution to the problem of keeping locomotives with broken pantographs in service: if an engine’s array was broken, it could simply plug into an adjacent Rectifier.

The Williams engine is not designed to actually do that, but it does simulate a plug-in near the pantograph, running along the top of the body, and inserted into the rear of the roof. Look very closely at the prototype photo and you will discover two units operating with one pantograph, and just barely visible is a jumper line connecting the two via the electrical conduit on top! This is another one of those details that would have been easy for Williams to ignore, but someone thoughtfully decided it was important enough to include.

@hokie71 posted:

Check this 2006 review of the williams rectifier, maybe the answer?

https://www.trains.com/ctt/new...-rectifier-electric/

Of special note is “the plug.” The Rectifiers had a unique resolution to the problem of keeping locomotives with broken pantographs in service: if an engine’s array was broken, it could simply plug into an adjacent Rectifier.

The Williams engine is not designed to actually do that, but it does simulate a plug-in near the pantograph, running along the top of the body, and inserted into the rear of the roof. Look very closely at the prototype photo and you will discover two units operating with one pantograph, and just barely visible is a jumper line connecting the two via the electrical conduit on top! This is another one of those details that would have been easy for Williams to ignore, but someone thoughtfully decided it was important enough to include.

Thank you @hokie71. Oddly, my powered E-33 does not say "W/Plug" on the box label; but, being a WBB product, I guess that Bachmann did not carry the labeling forward.

One thing that the article does not mention is that the hoods are about two feet taller than the prototype when set next to a scale E-33; probably to clear the vertical motored "China drive" components. We also compared it to a Locomotive Workshop scale E-44. Anyway, that really does not detract anything from the model and would only be noticeable if you have it next to an E-44. Note that the prototype E-33 and E-44 did not MU.

Could it be for a sound system?