The NMRA group has defined a standard for interfaces between decoders, locomotives and rolling stock. As I will do a lot of DCC installations in the near future, I will standardize the colors of the wires according to the NMRA standard as much as possible. Of course, if manufacturers like LGB and PIKO adhere to these standards, I would need to replace the wiring. If it’s not too much hassle, I will do this, otherwise I leave it as is and make sure to label the wires correctly.

Link: NMRA S-9.1.1 (external link – PDF)

One major difference between the NMRA and typical Large Scale locomotives is the travel direction. If you wire up a locomotive according to the NMRA standard, the locomotive will drive in the opposite direction of for example a factory DCC locomotive from LGB or PIKO. It’s a historic thing, but it’s something to take into account. So for the motor control section below, I will probably need to swap the +/- connections around.

Where I’ll follow NMRA:

• Track Power
  • Red – Track, Right Rail
  • Black – Track, Left Rail
• Motor Control [to be confirmed]
  • Orange – Motor (+)
  • Grey – Motor (-)
• Lighting (Directional)
  • Blue – Lighting (+) Common
  • White – Lighting (-) for Front (Output 1)
  • Yellow – Lighting (-) for Rear (Output 2)
• Other
  • Violet – Speaker

For other connections and/or accessories (cab lighting, uncouplers, …), I will probably use Green or Brown as those two colors are also in the pack of wires I purchased.