I am working on the same project. I have a USRA Light 2-10-2 Spectrum apart and have installed the speaker in the tender. I want to hard wire the Tsunami and replace the original decoder and plug and play board. However I am not sure which wires coming form the engine are correct. There are two connectors one has 4 pins and the other two. The two pin has a red and back wire which I assume is track pickup as they connect to the board in the same location as the tender pickup wires are connected. As for as the four pin I have a red, orange, brown and yellow wire. Any idea which is motor + and motor - and the + & - headlight? Thanks