This model dates back to the early days of N scale (late 60s / early 70s). It was originally (and briefly) imported by MRC, after which it became part of the Aurora/Minitrix "old timer" series. ATI / Model Power became the importer after that.
I'm not sure what specific prototype this model might be based on (if any), but it looks a lot like the double sheathed box cars designed by the USRA (United States Railway Administration) during World War I. The double sheathed version was the first widely accepted 40-foot steel underframe box car placed in service. Some 24,500 cars were delivered to 24 different railroads throughout the country.
The steel roof on this particular model would seem to make it some sort of rebuild job, thus moving it forward in time a bit (1930s or 1940s). Not that Roco actually cared about such things - I'm sure the steel roof was simply recycled from some other model in order to save some money on tooling costs.