I just did a complete overhaul on 2 of these cars. I got them with a log loader on a Stout auction several months back. They're a little trickier than you might think. The picture from @ADCX Rob isn't of a sliding shoe truck, so it's a bit harder (for me at least). First of all, as @Alan Mancus stated, the insulation on the wires is probably disintegrating. If not, skip to the next paragraph. If so, first take a picture of how they're connected to the fiber (?) boards that are connected to the solenoid. Since I had 2 cars, I didn't have to take pics since I could refer to the other one. I was not able to solder the connection to the sliding shoe without taking the wheels and trucks apart. If you can do that, great, easy peasy. You may have to take apart the fiber boards as well (I did). I'm an 'okay' solderer (took some time), but not great. I was able to get 3 out of 4 the sliding shoe connections (2 cars, remember) resoldered, but on 1 I destroyed the little frame it's on. That part number is 483-2. You might want to check with Jeff at ttender for it, if not then the bay. Jeff may also have a replacement for your missing stake.
The plunger may need some TLC to raise up with enough force, I put a tiny amount of model grease on it, and it worked wonders.
Lastly, the hinge to which the lifting plate is connected will need some TLC as well. Clean it thoroughly, also the little brass (?) arm which I guess kind of holds it up. Then, apply the lubrication you think it right on those spots.
This is what I did, and they now work great. YMMV.
