Identifying colored wires used in lights on GP-30

[Grapevine Flyer]

There are 4 colored wires that lead to small circuit boards that power the lights on a Williams GP-30:  red, black, yellow, blue.

Can someone please tell me what sort of power runs through these 4 colored wires?

Is black ground? Is red Track voltage? What are blue and yellow?

Any help is appreciated.

[trainyardjp]

JP, of Acton MA, USA writes:
If black is ground, and red is track power, the blue and yellow wires, are likely connected to the lights (probably)
Without seeing pics, or having a GP30, of my own, I can only speculate. Perhaps 3 Rail or the 'Bach Man', might be able to
more accurately answer your question.
-JP

[phillyreading]

JP, not sure but you might have two of the wires wrongly identified. Black is most likely the common(and you are probably correct, red could be track power and correct again) however the other two wires, blue & yellow, go to the motors for speed control. The lights get their power from the black & red wires.
To be 100 percent correct trace the wire from the pick-up point and see where it goes. Whatever wire attaches directly to the metal frame is considered negative or common. The wire that goes from the center rail pick-up is the hot wire and should go to two locations; first is the light socket, second is to the motor control unit. The wires from the motor control unit go to the motor. There can be 3 wires that go to the motor area; one is a common and goes to the frame(not always there on all models) the other two wires go the motor area from the circuit board and control the motor speed & direction because most Williams engines have DC can motors(sealed motors) in them. Before I forget there can be another set of wires that go to a horn unit and come out of the motor control unit area.

If the Williams engine has what looks like an open frame construction or post war Lionel look of the 1960's it is an early Williams engine and has an AC motor. FYI: not many left of that model so chances of finding one are very slim.

Lee F.