complete with original Campagnolo dropouts, the teeth are in excellent condition. It was common to also found the dropouts with the teeth filed away, so a normal axle could be used in the dropouts.
the rear axle locknut is stamped "CAM 49," so it is dated 1949. pretty cool.
The way chain was moved into another cog on the freewheel(3 spd and 4 speed were common) was to open the long quick release lever to the rear hub, then simultaneously backpedal and move the shift lever to derail the chain onto a different cog. Once you were in the desired cog, to then close the wheel quick release.
the tension of the chain was adjust by the angle of the dropout and the rider's weight on the bike. The wheel would move fore and aft depending upon the gear combination, there was no sprung jockey wheels.
Keep in mind riders in the 1940s Tour De France raced with this system and even won!
see video I found online.-