Over the course of several years I've been trying to find vintage toy buses that were as close to true O-gauge or O-scale that I could which would be around that 1/43 to 1/50 scale range. Toy maker's back in the day didn't care about scale or what things looked like on some kid's toy train layout, they made toys to play with. On the one hand, this does make it fun when trying to flesh out a layout with vehicles but it gets a little frustrating trying to find proper O-gauge stuff. Based on my collecting the bottom line is this: only Keystone was the only U.S. company which made plastic toy buses fully O-gauge compatible. BUT they weren't widely available, only being included in Keystone playsets. Buses made by all other companies were diminutive by comparison. That being said, today's featured bus really does look good when displayed alongside the Built-Rite cardboard buildings that were on my train layout up until a month or so ago.
I posted one of these back in 2014 but my sample back then had a hole in the front, a void created by the plastic not filling the cavity all the way during casting. At 4 1/2" (11.43cm) L x 1 1/2" (3.81cm) W x 1 1/4" (3.17cm) H this is a good representation of mid-50's Metro RTA type bus - at least that's the way it appears to me but I'm not a bus expert and this may represent another model bus altogether. Enjoy!