https://k3dug.smugmug.com/Other/General-Photos/i-JffgFkK/A is what I found inside the loco. Looks like a solder header. The wire color seems to follow NMRA DCC decoders. The chassis of the motor is isolated from the wheels. No place for a speaker but it looks like the Bachmann decoder with wiring harness would fit. Any body disagree?