@Carey Williams posted:
Hawk ( wood model airplane maker out of Chicago ) offered an O scale helium car kit 1938-41 .
I have seen and chased after 3-4 of those Hawk kits and then 5-6 built up cars. Both sell for too much vs. the amount of time and effort I'd have to invest in them to bring them up to something I could accept. Someday, maybe 1 will show up that fits my budget.