I had a crude HO gauge train in the 50s that must have been clockwork -- I don't remember batteries and it wasn't electric. Metal track (similar to AF) and there were 2 poles that it spiraled up and then down.
I know that there was clockwork in OO gauge from England. Hornby Dublo started with clockwork and electric models of a Pacific and 0-6-2T. I have a later clockwork tank engine. I'm sure even TriAng made a clockwork loco in the 50s.
I think there were still places that didn't have an electric connection until well after the war, and there were mothers who wouldn't trust their precious with a wall plug.