@Jim Starbuck - always SO inspiring!
Just curious - how are the trucks attached to/retained by the frame/shell?
I glued small pieces of styrene square stock to the sides of the slot in the chassis then with a half round file made a crescent shape that allows the truck to pivot. Then the trucks snapped in between the styrene strips when inserted from inboard. There’s just enough of the truck tabs left to hold the truck in after filing them shorter to fit inside the narrow hood.
This is what needs to be reworked though as the trucks unsnap front to back when running. I’m going to make a wafer of .020” styrene with a hole big enough for the gear tower to pivot ( it doesn’t require hardly anything) an
then file keyhole slots so the trucks can be inserted upwards into the styrene then turned to engage the worm and what’s left of the truck tabs. I’ve only got about .045” total to work with between the truck pivoting, the tabs fitting inside the shell and the truck falling out.