Dave
Lackawanna Route of the Phoebe Snow
Your grey controller box for the TT has at least three input/output terminals beneath it, on one side. One is for the motor controller and power to the tracks, and that is the thick cable that comes with the TT. It can only enter one specific socket on that side of the grey controller box. Right next to that socket are two small terminals for the feeders that come off your bus. If you have no bus, simply run another set of feeders off the DCC main station output terminals and run them into those two power terminals. Those two wires provide the bridge rails with the DCC signal...and that's all they do. The power to turn the motor for bridge function comes from a separate power source, and that you must supply yourself. I asked around at electronics supplies stores and found one that had a used 16v AC power supply, a black wall wart that topped out at 0.5 amps, which I seem to recall fits nicely in the range allowed by Walthers.
So, the DCC signal to make your engines stay alive on the bridge comes from the two thin feeder wires that are pressed into two receptacles immediately adjacent to the big cable's receptacle. In turn, they must tap into your bus or come off the main outputs on your DCC system's base station.
Does that help?
Edit- crossed out confusing (and wrong) text. The thick cable only controls the motor and its indexing electronics. The two thin feeders that nest beside it in their own receptacles power the rails...period. Your power supply only feeds the thick cable. Your DCC system feeds the engine on the bridge via the two thin feeders. Sorry if I caused anxiety or confusion.
73
Bruce in the Peg
Bruce, the manual (really a large folded sheet or two) that came with my 90'er says you have a choice of DC or AC and that you must have voltage between 12 volts and a max of...19 I think it was? So, I opted to buy the used wall wart that this fellow said he had on hand, and it was 16 volts AC with a max of 0.5. The guy said he would test it out for me before he would sell it to me, and it checked out...apparently. So far, no hiccups.
-Crandell