The Budd Rail Diesel Car (RDC), also known as the Budd car or Buddliner, is a self-propelled diesel multiple unit (DMU) railcar. Between 1949 and 1962, 398 RDCs were built by the Budd Company of Philadelphia, Pennsylvania, United States. The cars were primarily adopted for passenger service in rural areas with low traffic density or in short-haul commuter service, and were less expensive to operate in this context than a traditional diesel locomotive-drawn train with coaches. The cars could be used singly or coupled together in train sets and controlled from the cab of the front unit. The RDC was one of the few DMU trains to achieve commercial success in North America. RDC trains were an early example of self-contained diesel multiple unit trains, an arrangement now in common use by railways all over the world.
Budd RDCs were sold to operators in North America, South America, Asia, and Australia. They saw extensive use in the Northeast United States, both on branch lines and in commuter service. As passenger service declined in the United States the RDC was often the last surviving conveyor of passengers on a particular route. Most RDCs were retired by the 1980s. The cars remain in service in Canada, where RDCs continue to on normally the Sudbury–White River line, and have remained in continuous use since their introduction in the 1950s.
The RDC inspired several derivatives, including the unsuccessful Budd SPV-2000. The New York Central Railroad installed two jet engines on an RDC in 1966 and set a United States speed record of , although this experimental configuration was never used in regular service.
Background
The self-propelled railcar was not a new concept in North American railroading. Beginning in the 1880s railroads experimented with steam-powered railcars on branch lines, where the costs of operating a conventional steam locomotive-hauled set of cars was prohibitive. These cars failed for several reasons: the boiler and engine were too heavy, water and fuel took up too much space, and high maintenance costs eliminated whatever advantage was gained from reducing labor costs. In the 1900s steam railcars gave way to gasoline, led by the McKeen Motor Car Company, which produced 152 between 1905 and 1917. The J. G. Brill Company sold over 300 railbuses in the 1920s. Newcomer Electro-Motive Corporation, working with the Winton Motor Carriage Company, dominated the market at the end of the 1920s but had left it completely by 1932 as the Great Depression gutted rail traffic.
The Budd Company entered the market in 1932, just as EMC left. Until then, Budd had been mainly an automotive parts subcontractor, but had pioneered methods for working with stainless steel, including the technique of shot welding to join stainless steel components. This permitted the construction of cars which were both light and strong. Budd partnered with Michelin to construct several rubber-tired 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 under-powered, 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 weighed empty. The RDC-9: an passenger trailer seating 94, a single engine and no control cab.
Several railroads used the designation "RDC-5": the Canadian Pacific Railway for RDC-2s converted to full-coach configuration and the Canadian National Railway for RDC-9s it purchased from the Boston and Maine Railroad. The Baltimore and Ohio Railroad had a pair of its RDC-2s equipped with a small kitchen, 24 seats in a dining area, and 24 seats in a coach section. One is preserved at the B&O Railroad Museum.
In 1956, Budd introduced a new version of the RDC, with several improvements. The new cars had more powerful versions of the Detroit Diesel 6-110 engines, each of which produced instead of . They also featured higher-capacity air conditioning and more comfortable seating. The appearance changed slightly as well: the side fluting continued around to the front of the car and the front-facing windows were smaller.
Jet propulsion
In an experiment toward high-speed rail, the New York Central Railroad fitted a pair of General Electric J47 jet engines from a Convair B-36, complete in their twinned nacelle from the bomber's engine installation, atop one of their RDCs and added a shovel nose front (much like a later automotive air dam) to its cab, but extended upwards, covering the entire front end. This RDC, which NYC had numbered M497, set the United States speed record in 1966 when it traveled at just short of between Butler, Indiana, and Stryker, Ohio. It was never intended that jet engines propel regular trains. With high-speed trains advancing overseas, particularly the Japanese Shinkansen bullet trains, American railroads were under pressure from the federal government to catch up. The test runs and subsequent American rail speed record set on July 23, 1966, provided valuable data on the interaction between flanged wheels and rail at high speeds, as well as stress on wheel bearings and track infrastructure.
At the same time the test took place, the Central announced plans to discontinue most of its long-distance trains, including the renowned 20th Century Limited. Trains editor David P. Morgan observed that "...[the New York] Central will never quite convince anyone that the RDC's jet exploit was more a scientific feat than a calculated circus to take the curse off the Centurys funeral notice." Historian Chuck Crouse expressed skepticism in 1990 about the test's usefulness: "What, if anything, did the tests prove is anyone's guess."
Derivatives
In 1956, the New York, New Haven and Hartford Railroad ordered a custom-built, six-car train set they named the Roger Williams, based on the RDC design. It consisted of two single-ended cab units and four intermediate cars to make a complete train. The units were fitted with third-rail shoes, electric traction motors, and associated gear for operation into Grand Central Terminal, though this was short-lived. In the New Haven's later years, the set was broken up, and used with regular New Haven RDCs, and by Amtrak into the 1980s.
In 1961, five cars were built under license in Australia for the Department of Railways New South Wales. They were shorter and narrower than the North American models.
In 1966, Tokyu Car built 31 DR2700 series cars for the Taiwan Railway Administration. Tokyu got a licence from the Budd Company and the bodywork of the DR2700 series was based on the RDC. There were 25 powered driving cars (each with a Cummins diesel engine producing ) and 6 trailers. The DR2700 series was the fastest train in the following decade with a top speed of . They were withdrawn from regular service in 2014 while several powered driving cars were still active for special trains.
In the late 1970s Budd sought to replace the aging RDCs with a new design, the SPV-2000. The body shell was based on an Amfleet coach, not the RDC. Like the RDC it was long, stainless steel, and powered by twin diesel engines. The design was beset with mechanical problems, and Budd sold only 30 cars.
From 1982 to 1984 Tokyu Car built 45 of a heavily specialized, meter-gauge RDC design for the Taiwan Railway Administration under license from Budd. Designated the DR2800 series, the units are organized into 15 permanently-coupled three-car sets (30 powered driving cars and 15 trailers). Like other RDC trainsets before them, each cab unit only has a cab at one end and two cab units bracket a trailer in a standard set. Unlike other RDC sets, however, the trailer's diesel engine is used exclusively to provide head-end power for the entire three-car set, while the engines in the driver cars are used for propulsion. To prevent dependency on the trailer's engine for cooling, the cooling fans of the driver cars are driven hydraulically instead of electrically. This configuration results in each set producing for a top speed of . All 15 sets were still in service by 2022; they were withdrawn from service on April 26, 2023.
History United States
The vast majority of RDCs were owned and operated by railroads in the United States. They could be found on branch lines, short-haul intercity routes, commuter routes, and even long-distance trains. The Western Pacific Railroad used a pair of RDC-2s to operate the Zephyrette, a supplement to the California Zephyr. The two cars ran between Oakland, California and Salt Lake City, Utah, , three days a week. Examples of shorter intercity services were the Chicago, Rock Island and Pacific Railroad's Memphis, Tennessee–Amarillo, Texas Choctaw Rocket and the Baltimore and Ohio Railroad's Daylight Speedliner. The latter ran between Pittsburgh and Philadelphia and included full dining service. A notable example of the RDC's flexibility occurred on the Pennsylvania-Reading Seashore Lines, where a single train would depart Camden, New Jersey and split into multiple trains to serve different destinations on the Atlantic coast.
The largest RDC fleets were in the Northeast United States. The New York, New Haven and Hartford Railroad (New Haven) acquired 40 RDCs, which it called "Shoreliners", in 1952–53. By 1955 these accounted for 65% of the New Haven's passenger routes. This achievement was eclipsed by the Boston and Maine Railroad, whose fleet grew to 108 by 1958. The B&M's RDCs operated 90% of the company's passenger routes, including its extensive commuter operations around Boston, Massachusetts.
The results in commuter service outside the B&M were mixed. Budd had not designed the RDC for commuter service and discouraged operators from using it to haul coaches. The Long Island Rail Road and Chicago and North Western Railway, which had extensive networks in Long Island and Chicago, respectively, evaluated the RDC but made few orders. Conversely, the Reading Company's 12 RDC-1s lasted on the Philadelphia–Reading and Philadelphia–Bethlehem routes well into the SEPTA era.