RDCs were manufactured throughout the 1950s by Budd Company of Philadelphia. The 1950s was the decade during which the popularity of passenger trains
Between 1949 and 1962, Budd Company, in Philadelphia, built a total of 398 self–propelled passenger RDCs, which came in 5 types. All were equipped with 2 Detroit 6/110 Diesel engines rated to 250–280 HP, each connected to the inner axle of each truck by a drive shaft. RDCs were rated for a top speed of 85 MPH. However, in 1966 New York Central modified RDC #M497 with jet engines on the top and ran it to a top speed of 184 MPH, which is still the record in the United States of America. The car body was similar to Budd Company's streamlined, corrugated, passenger cars, and were all 85 feet long (except RDC–4). While most of the RDCs vanished from regular service, a few survived, like the ones in service for Trinity Railway Express (TRE) in Dallas, Texas, or a few for VIA Rail Canada, Inc.
RDCs were produced in 5 types. An RDC–1 is a full coach with 2 cabs and standard seating of 90 seats . This is the type of our RDCs, #9153 and #9167. The RDC–2 has a small baggage compartment at the F end of the car and is a coach with 70 seats. Similar to this is the RDC–3, which has in addition a Rail Post Office (RPO) compartment at the F end of the car, a baggage compartment and a coach with 49 seats.
Special RDCs were RDC–4 and RDC–5. RDC–4 had only the RPO and baggage compartments. RDC–9 had only one engine to drive one truck and also provide power for lights, air conditioning, and heat. It had no cab. It was used as an intermediate car, between others equipped with cabs and dual engines, to allow for greater passenger capacity.