For each engine, the motors are wired in parallel, from an electronic reverse board. I can differentiate the track pickup wire and the ground wire on the board. That leaves me with two wires out to the motors. I assume on here of these is DC+, and the other is DC-. Does it matter which wire I insert the diode string into? I don't think it should, but I'd like a second opinion. I just tapped into whatever was the more colored wire, as silly as it sounds. They seem to work well.
Thanks, Chris