As for wiring, the cream wiring going to the coils appears to be the original. This wiring is notorious for shorting out due to the insulation flaking off as it ages.
You will probably need to disassemble and clean clean clean, then rewire the motor. The little clips you see on the edges of the fiber board are for the directional headlights. You connect one light to each side for power and it activates based upon direction (position of the reverse unit). If it's backwards compared to direction, then swap the wires.
The main difference (extra wiring) for an R/C motor is to energize that coil you see near the reverse unit. When powered, that coil energizes and lifts upwards, lifting the rod that catches on the little cam that spins between the drivers (inside the frame of the motor) on the brush side of the motor block (look in there closely). If the coil does not properly lift this rod all the way up, then it will catch the cam and inhibit the motor from running freely. When you disengage R/C, that lever is manually pulling that catch rod upwards and off of the spinning cam.
In a properly operating motor, when youre running at speed and cut power, the coil releases the catch rod, which falls, and the cam yanks it, thus mechanically shifting the reverse unit to change direction (you'll see the roof top lever flip). The locomotive will still coast a bit, because there is a clutch built into that little cam that allows it to slip. If your catch rod is stuck against the cam, it cannot be raised, and thus the motor will not run.
First try this. Put the motor on the track with the cam facing you. Manually use the R/C control lever to raise and lower the cam catch rod, studying how it works. You may need to rotate the wheels a bit to free it up so it raises as it can get stuck under the spinning cam. Once it's loose, rotate the wheels a bit to put the cam "wings" off to the sides so as not to catch the rod. Engage R/C, and power it up to make sure the rod is being lifted above the cam by the coil. If the rod is stuck under the cam, sometimes you can force the motor to run, but it will be sluggish and slow because the motor is dragging against the cam clutch. You will almost always need to check it for freedom each time you run it. If it is stuck, it can also try to yank on the reverse lever as you try to run it, thus traveling an inch or two before seemingly shorting out and it will just sit there and hum, or loose power completely.
The key to success with these is to keep them very clean, lubricated, and have good electrical connections. Some of the R/C coils are electromagnets. Some have a plunger and bracket that lift the rod. It varies by when the motor was made. If the R/C coil is bad, it will not function, but this is a rare failure. Lots of fiddling to make it work well is normal. I make them work, but tend to lock all my locos into manual mode for reliable running.
Sorry this is so long. Hopefully it helps.
