---In STMFC@..., <gary@...> wrote :
The Rr-56 would be a very desirable model with a significant number built in the later 1950s.
I model the early 1960s. The other class that attracts my attention is Rr-69 with 500 built in 1961.
The SFRD Class Rr-56 contained 233 cars built in 1955. A fit for the very, very late steam era plus the diesel era. Santa Fe had 191 of these cars on the roster as late as 1971.