You would need to install all new lighting for the locomotive since the polarities are switched for LEDs on MTH ho DCS/DCC. IMHO, MTH PS3 on ho is not great compared to ESU, TCS or Tsunami 2. I have had a few problems with ho PS3. I would look into ESU loksound V4 or the new V5. The Bachman’s DCC I’m board have cheap decoders plugged into an 8 pin plug in the tender. DCC sound value have a hard wired decoder. Depending on which the loco is, the difficulty to install will vary. The DCC on board can have the decoder just pulled out and a sound decoder plugged into the slot. If it has sound, it will need to be gutted and completely rewired. You should check out all of your options before you jump on PS3. As stated before, I do not believe MTH has HO PS3 boards available for install. The use a custom plug and harness wired into the locomotive. (Atleast on my GP38.) I recommend tsunami 2 decoders if the loco is sound value. For $110, it really is a great decoder. If it is DCC on board with a decoder just plugged in, I would go with ESU because they are essentially plug and play. If you want to see sound examples, YouTube has plenty.
Hopefully I could help!
