Circus Craft Kits were produced by Frank Crumrine in LaMesa & San Diego Ca from 1968 to the late 1990s when I belive Frank Crumrine passed away. I do not know if anyone took it over after that.
The kits are wood , circus wagons ,Warren flat car , elephant car and stock car. They where in O ,G & HO size. The kits come up on ebay , HO seems to be the most common.
Years ago I acquired a bunch of circus craft kits in O & G. The G works with standard gauge. Occasionally when it rains in So Calif, I put one together. I haven't made much progress , but I have put a few together. They go together easy with good instructions ,I like Northeastern Flamingo glue for wood kits.