Boston and Maine Railroad Budd 4-car RDC train in 1969.

(Roger Puta, via Marty Bernard, railfan 44, Public domain, via Wikimedia Commons)



The Budd Rail Diesel Car, RDC, 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.


Interior of the RDC-1 demonstrator in 1949.

(Lewis and Gilman, public relations for the Budd Company, Public domain, via Wikimedia Commons)


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. In Canada, RDCs 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 strapped two jet engines to an RDC in 1966 and set a United States speed record of 184 mph (296 km/h), although this experimental configuration was never used in regular service.


Budd's Prospector in 1941. Click to enlarge.

(Employees of the Budd Company, Philadelphia, Public domain, via Wikimedia Commons)



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 exited it completely by 1932 as the Great Depression gutted rail traffic.

The Budd Company entered the market in 1932, just 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-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 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 192 horsepower (143 kW) 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.



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 85-foot (26 m) coach design and added a pair of 275 hp (205 kW) 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 85 miles per hour (137 km/h). 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.


An ex-Canadian Pacific Railway RDC-4 in 2007. Click to enlarge.

(Flowizm ..., CC BY 2.0 <>, via Wikimedia Commons)



Budd manufactured five basic variants of the RDC:

  • The RDC-1: an 85 ft (25.91 m) all-passenger coach seating 90 passengers. It weighed 118,300 pounds (53.7 t) empty.
  • The RDC-2: an 85 ft (25.91 m) baggage and passenger coach configuration (combine) seating 70 passengers. The baggage area was 17 ft (5.18 m) long. It weighed 114,200 pounds (51.8 t) empty.
  • The RDC-3: an 85 ft (25.91 m) variant with a railway post office, a baggage compartment and 48 passenger seats. It weighed 117,900 pounds (53.5 t) empty.
  • The RDC-4: a 73 ft 10 in (22.50 m) variant with only the railway post office and baggage area. It weighed 109,200 pounds (49.5 t) empty.
  • The RDC-9: an 85 ft (25.91 m) passenger trailer seating 94, a single 300-horsepower (220 kW) 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.

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 300 horsepower (220 kW) instead of 275 horsepower (205 kW). 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

Main article: M-497 Black Beetle

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 184 mph (296 km/h) 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 Century's 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."


The Roger Williams at the Danbury Railway Museum in 2006. Click to enlarge.

(Mike Powell, CC BY-SA 2.0 <>, via Wikimedia Commons)



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 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 85 feet (26 m) long, stainless steel, and powered by twin diesel engines. The design was beset with mechanical problems, and Budd sold only 30 cars.

In 1966, Tokyu Car built 31 DR2700 series cars for the Taiwan Railway Administration. Tokyu got a license 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 335 horsepower (250 kW)) and 6 trailers. The DR2700 series was the fastest train in the following decade with a top speed of 110 km per hour or 68 mph. They were withdrawn from regular service in 2014 while several powered driving cars were still active for special trains.

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 700 horsepower (520 kW) for a top speed of 110 km per hour or 68 mph. All 15 sets are still in service as of 2022.


Ex-B&M RDC-1 No. 6211 at the Bedford Depot in 2010. Click to enlarge. (John Phelan, CC BY 3.0 <>, via Wikimedia Commons)

Two All Earth Rail RDCs at St. Albans, Vermont, in 2018. Click to enlarge. (CodeJeffrey, CC BY-SA 4.0 <>, via Wikimedia Commons)

Ex-Alaska Railroad RDC-2 units in WES Commuter Rail service, in Oregon, in 2017. Click to enlarge. (Steve Morgan, CC BY-SA 4.0 <>, via Wikimedia Commons)



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, 924 miles (1,487 km), 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.

For several railroads the RDCs, because of their low overall cost and operational flexibility, were the last passenger trains in operation. Examples include the Duluth, Missabe, and Iron Range Railway, the Duluth, South Shore and Atlantic Railway, the Lehigh Valley Railroad, and the Northwestern Pacific Railroad, where RDC service survived until the formation of Amtrak in 1971.

Many RDCs remained in service throughout the 1970s and 1980s. Amtrak acquired 24 (including three from the Roger Williams), mostly for use in Connecticut. The Massachusetts Bay Transportation Authority (MBTA) acquired the B&M's fleet and continued operating them until 1985. The Alaska Railroad acquired five RDCs, three from SEPTA and two from Amtrak between 1984 and 1986. These were all sold or out of service by 2009. Trinity Railway Express acquired thirteen RDCs from Via Rail in 1993 for use on commuter service between Dallas and Fort Worth, Texas. The Denton County Transportation Authority leased several for A-train service pending the arrival of new Stadler GTW 2/6s diesel multiple units.

Despite their advanced age, a market for Budd RDCs has continued. Oregonian transit authority TriMet purchased and refurbished two RDCs in 2009 to provide backup for its commuter rail service, WES, following reliability issues with the primary DMUs for that service, which had been purpose-built by Colorado Railcar. In 2017, a Vermont company, AllEarth Rail, bought twelve 1959 Budd cars from Dallas Area Rapid Transit for $5 million. The cars had previously been owned by Via Rail Canada, which also bid on the lot. AllEarth said it planned to use the cars for commuter rail service in Vermont, possibly starting with a Burlington-to-Montpelier route. TriMet subsequently purchased two of these cars from AllEarth later the same year, in addition to its existing two, and stated they would enter WES service in 2021; however, those plans were postponed indefinitely in view of a COVID-19 pandemic-related ridership decline.


Canadian National RDC-1 No. 1501 at Portage Junction in Winnipeg on May 2, 2014. Click to enlarge.

(Taylorover9002 at English Wikipedia, CC BY-SA 4.0 <>, via Wikimedia Commons)



Both the Canadian National Railway (CN) and Canadian Pacific Railway (CP) purchased RDCs. The Canadian National purchased 25 cars outright, and acquired many more second-hand from the Boston and Maine Railroad. These cars, which CN called Railiners, were used primarily on secondary passenger routes. CP purchased 53 cars. The first one ran on November 9, 1954, between Detroit and Toronto. It was the first stainless-steel passenger train to operate in Canada. CP used the RDCs, which it called Dayliners, throughout its system. CP also made extensive use of them on commuter trains around Montreal and Toronto. Via Rail inherited many of these cars when it took over CN and CP passenger services in 1978. Via continues to use RDCs on the Sudbury–White River train in Ontario.

Another Canadian purchaser of RDCs was the Pacific Great Eastern Railway, which operated passenger service between North Vancouver and Prince George. RDCs continued to operate on this route until all passenger service ended under BC Rail, PGE's successor, in 2002.

Refurbished RDCs were considered for Blue22, a rail service between Toronto Union Station and Pearson Airport, by 2010. The service, which was transferred to Metrolinx ownership and opened in 2015 as the Union Pearson Express, ultimately used new Nippon Sharyo DMU trains instead.


Original owners

Budd constructed 398 RDCs between 1949 and 1962. The list below does not include the six cars which comprised the Roger Williams, nor derivative designs built under license.

Railroad / Model / Quantity / Road Numbers / Notes
Arabian American Oil Company / RDC-2 / 4 / 8000–8003
Atchison, Topeka and Santa Fe Railway / RDC-1 / 2 / DC-191, DC-192 / After a 1956 wreck, the DC-192 was rebuilt as an RDC-2.
Baltimore and Ohio Railroad / RDC-1 / 12 / 1908–1911, 6510–6517
Baltimore and Ohio Railroad / RDC-2 / 4 / 1960–1961, 6550–6551
Boston and Maine Railroad / RDC-1 / 57 / 6100–6156
Boston and Maine Railroad / RDC-2 / 15 / 6200–6214
Boston and Maine Railroad / RDC-3 / 7 / 6300–6306
Boston and Maine Railroad / RDC-9 / 30 / 6900–6929
Budd (prototype/demonstrator) / RDC-1 / 1 / 2960
Canadian National Railways / RDC-1 / 9 / D-200–D-201, D-102–D-108
Canadian National Railways / RDC-2 / 5 / D-201–D-203, D-205, D-250
Canadian National Railways / RDC-3 / 5 / D-100–D-101, D-302, D-351–D-352
Canadian National Railways / RDC-4 / 6 / D-150–D-151, D-401–D-402, D-451–D-452
Canadian Pacific Railway / RDC-1 / 23 / 9050–9072
Canadian Pacific Railway / RDC-2 / 22 / 9100–9115, 9194–9199
Canadian Pacific Railway / RDC-3 / 5 / 9020–9024
Canadian Pacific Railway / RDC-4 / 3 / 9200, 9250–9251
Central Railroad of New Jersey / RDC-1 / 7 / 551–557
Chicago and Eastern Illinois Railroad / RDC-1 / 1 / RDC1
Chicago and North Western Railway / RDC-1 / 2 / 9933–9934
Chicago and North Western Railway / RDC-2 / 1 / 9935
Chicago, Rock Island and Pacific Railroad / RDC-3 / 5 / 9002–9004, 9015–9016
Commonwealth Railways (Australia) / RDC-1 / 3 / CB1–CB3
Consolidated Railways of Cuba / RDC-1 / 11
Consolidated Railways of Cuba / RDC-2 / 5
Duluth, Missabe and Iron Range Railway / RDC-3 / 1 / 1
Duluth, South Shore and Atlantic Railway / RDC-1 / 1 / 500
Duluth, Winnipeg and Pacific Railway / RDC-3 / 1 / D301
Grand Trunk Western Railroad / RDC-2 / 1 / D204
Grand Trunk Western Railroad RDC-3 / 1 / D303
Great Northern Railway RDC-3 / 1 / 2350
Lehigh Valley Railroad RDC-1 / 1 / 40
Lehigh Valley Railroad RDC-2 / 1 / 41
Long Island Rail Road RDC-1 / 1 / 3101
Long Island Rail Road RDC-2 / 1 / 3121
Minneapolis and St. Louis Railway / RDC-4 / 2 / 32–33
Missouri-Kansas-Texas Railroad / RDC-3 / 1 / 20
New York Central Railroad / RDC-1 / 16 / M-451–M-465
New York Central Railroad / RDC-2 / 1 / M-480
New York Central Railroad /RDC-3 / 3 / M-497–M-499
New York, New Haven and Hartford Railroad / RDC-1 / 29 / 20–48
New York, New Haven and Hartford Railroad / RDC-2 / 2 / 120–121
New York, New Haven and Hartford Railroad / RDC-3 / 6 / 125–130
New York, New Haven and Hartford Railroad / RDC-4 / 3 / 135–137
New York, Susquehanna and Western Railway / RDC-1 / 4 / M-1–M-4
Northern Pacific Railway / RDC-2 / 1 / B30
Northern Pacific Railway / RDC-3 / 2 / B40–B41
Pacific Great Eastern Railway / RDC-1 / 3 / BC10–BC12
Pacific Great Eastern Railway / RDC-3 / 4 / BC30–BC33
Pennsylvania-Reading Seashore Lines / RDC-1 / 12 / M-402–M-413
Reading Company / RDC-1 / 12 / 9151–9162
RFFSA (Brazil) / RDC-1 / 8 / ED11–ED14, M504–M505, M552–M553
RFFSA (Brazil) / RDC-1 / 19 / M600–M610, M700–M707
RFFSA (Brazil) / RDC-2 / 2 / ED51–ED52
Southern Pacific Railroad / RDC-1 / 1 / 10
Western Pacific Railroad / RDC-2 / 2 / 375–376
Western Railroad of Cuba / RDC-1 / 4 / 901–904
Western Railroad of Cuba / RDC-3 / 6 / 951–956



Numerous RDCs have been preserved on tourist lines and in museums. Holders include:

Alberta Central Railway Museum
Bedford Depot
B&O Railroad Museum
Bellefonte Historical Railroad Society
Cape May Seashore Lines
Conway Scenic Railroad
Danbury Railway Museum
Hobo Railroad
Idaho Northern and Pacific Railroad
Illinois Railway Museum
Lehigh Gorge Scenic Railway
National Railway Museum of Australia
New Hope Valley Railway
North Shore Scenic Railroad
Orford Express
Port of Tillamook Bay Railroad
Railroad Museum of New England
Railroad Museum of Pennsylvania
Rapido Trains
Reading, Blue Mountain and Northern
Reading Railroad Heritage Museum
Waterloo Central Railway
West Coast Railway Association



In service: 1949–present
Manufacturer: Budd Company
Constructed: 1949–1962
Number built: 398
Capacity RDC-1: 90 passengers
Capacity RDC-2: 70 passengers, baggage section
Capacity RDC-3: 48 passengers, RPO, baggage section
Capacity RDC-4: RPO, baggage section
Capacity RDC-9: 94 passengers
Car body construction: Stainless steel
Car length
RDC-1/2/3/9: 85 ft (25.91 m)
RDC-4: 73 ft 10 in (22.50 m)
Width: 10 ft 0+3⁄8 in (3.06 m)
Height: 14 ft 7 in (4.45 m)
Maximum speed: 85 mph (137 km/h)
Weight 109,200–118,300 lb (49,500–53,700 kg)
Prime movers
RDC-1/2/3/4: 2 × GM 110 diesels
RDC-9: 1 × GM 110 diesel
Power output
RDC-1/2/3/4: 550 hp (410 kW)
RDC-9: 300 hp (220 kW)
Transmission: Hydraulic torque converter
Electric system: N/A
UIC classification
RDC-1/2/3/4: (1A)(A1)
RDC-9: (1A)2′
AAR wheel arrangement
RDC-1/2/3/4: 1A-A1
RDC-9: 1A-2
Braking system: New York Air Brake air brakes
Track gauge: 4 ft 8+1⁄2 in (1,435 mm) standard gauge