Update. I figured out the drive gear access; a generous application of clean grease really helped.
Questions: here is a shot of the air pumps:
...as you can see, they're mounted in opposite directions. Is this normal? Also...
Here is the lead truck: (get a load of the size of those flanges...! )
...the "arm" that connects it to the frame is attached solidly to the truck frame; there is no "secondary" pivot point. I don't think I've ever seen a pilot truck set up like this...is this weird, or is it just me?
Tons of fun...
Mark in Oregon