I finally electrified one of the MOW VW Buses.
Not exactly like that......
The shoe is curved and hugs the tube rail top. Inside there is a spring washer and 2 jam nuts on the screw so the copper shoe is sprung. Plastic drive whels might get swapped for metal to improve the connection. I needs two shoes or a big capacitor to stand a chance in turnouts.
Front wheels use a flex strip on the axle to deliver power (1/16" gab there.)
Motor is from a cassette tape player, the drive belt is a clear Goody hair elastic.
One down, three to go