as EMC exited. Up to that time Budd was primarily an automotive parts subcontractor, but had pioneered methods for working with stainless steel, including the technique of shot welding to join pieces of stainless steel. This permitted the construction of cars which were both light and strong. Budd partnered with Michelin to construct several rubber-tyred stainless steel rail cars powered by gasoline and diesel engines. These saw service with the Reading Company, Pennsylvania Railroad, and Texas and Pacific Railway. The cars were underpowered, the tires proved prone to blowouts and derailments, and the cars were unsuccessful. Budd revived its railcar concept after diesel engines with a suitable combination of power and weight became available in 1938, although with more conventional steel wheels. In 1941 Budd built the Prospector for the Denver and Rio Grande Western Railroad. This was a two-car diesel multiple unit. Each car had a pair of diesel engines and was capable of independent operation. The cars were constructed of stainless steel and included a mix of coach and sleeping accommodations. The design was popular with the public but undone by the difficult operating conditions on the D&RGW. It was withdrawn in July 1942, apparently another failure. However, several technical advances during the Second World War encouraged Budd to try again. Design During the years of the Second World War, there were improvements in the lightweight Detroit Diesel engines and, just as importantly, the hydraulic torque converter. Budd, which by then had produced more than 2,500 streamlined cars for various railroads, took a standard coach design and added a pair of 6-cylinder Detroit Diesel Series 110 engines. Each drove an axle through a hydraulic torque converter derived from the M46 Patton tank, for a 1A-A1 wheel arrangement. The top speed for the design was . The control systems allowed the cars to operate singly, or in multiple. The result was the RDC-1, which made its public debut at Chicago's Union Station on September 19, 1949. Variants Budd manufactured five basic variants of the RDC: The RDC-1: an all-passenger coach seating 90 passengers. It weighed empty. The RDC-2: an baggage and passenger coach configuration (combine) seating 70 passengers. The baggage area was long. It weighed empty. The RDC-3: an variant with a railway post office, a baggage compartment and 48 passenger seats. It weighed empty. The RDC-4: a variant with only the railway post office and baggage area. It