I’m in the process of redecorating a string of RDC cars to resemble the Boston MBTA’s early coaches from the 1980s. The “T” inherited quite the string of RDCs but many were beyond their self-powered life and required being drawn by locomotives.
Eventually the T started sending out the RDCs to Boise Idaho for rebuilding into Push-Pull commuter rail service. With push-pull cabs, the T could then control their new F40PH locomotives in push mode. Eventually the T phased out the RDC cars in favor of Pullman Comets (later Bombardier). Several of the RDC rebuilds made their way down to Metro North and now reside on the Grand Canyon RR. These cars had a more extensive rebuild, resulting in the removal of the roof top radiator vents.
Other RDC rebuilds retained their roof top humps and many of these have made their way to New Hampshire on the Hobo, and Winnipesaukee Scenic RR. Several are in service in scenic rail service as table cars and several remain in service.
I will be modeling the latter version (with humps), fully decorated in MBTA paint.