I am going to guess about 1974, although it might have been as much as 5 years earlier. They were all built without roofwalks, IIRC, and had crossover boards over the draft gear. I remember there was a big wreck involving mostly those cars at Belmont Avenue on the CB&Q "racetrack" which wiped out the center platform and goofed up commuter service for a couple of days..... fortuneately it happened early in the AM before the commuter rush and there were no injuries, which would not have been the case if it happened on one of the freights that sometimes snuck in during the commuter rush......and it was a platform that I normally got on the dinky into Chicago from! Charlie
Some of the Walthers HO ones had build dates as early as '69, but that's putting much faith in their research! Most of what they produced had early 70's dates though, sorry I have no experience of the prototype. I'm guessing these have basically been made obsolete by wrapped lumber and the centerbeam car? Would I be right in that? I certainly didn't see any during my last visit to the US (2000)
