The New York Central Railroad installed two jet engines on 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.

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.

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.

[6] Budd partnered with Michelin to construct several rubber-tired stainless steel rail cars powered by gasoline and diesel engines.

[8] 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.

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.

[note 1] 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.

The appearance changed slightly as well: the side fluting continued around to the front of the car and the front-facing windows were smaller.

[18] 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.

[21] 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.

"[23] 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.

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.

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).

This configuration results in each set producing 700 horsepower (520 kW) for a top speed of 110 kilometres per hour (68 mph).

The two cars ran between Oakland, California and Salt Lake City, Utah, 924 miles (1,487 km), three days a week.

[44] Trinity Railway Express acquired thirteen RDCs from Via Rail in 1993 for use on commuter service between Dallas and Fort Worth, Texas.

[45] The Denton County Transportation Authority leased several for A-train service pending the arrival of new Stadler GTW 2/6s diesel multiple units.

[47] In 2017, a Vermont company, AllEarth Rail, bought twelve 1959 Budd cars from Dallas Area Rapid Transit for $5 million.

AllEarth said it planned to use the cars for commuter rail service in Vermont, possibly starting with a Burlington-to-Montpelier route.

[48] 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;[49] however, those plans were postponed indefinitely in view of a COVID-19 pandemic-related ridership decline.

The Dominion Atlantic Railway (CP's subsidiary in Nova Scotia) also operated two RDCs lettered for its line.

[52][53] Another Canadian purchaser of RDCs was the Pacific Great Eastern Railway, which operated passenger service between North Vancouver and Prince George.

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.

Invariably referred to as "Budd cars", they operated between Port Pirie, Woomera, Tarcoola, Marree and Whyalla.

[58] In 1961, Commonwealth Engineering built five RDC-1 derivative cars[58] in Australia under licence for the New South Wales railways department.

[63] Age and mechanical problems led to the cars' conversion to locomotive-hauled coaches, beginning in 1982;[64] the last self-propelled run occurred in 1986.

The Arabian American Oil Company constructed a standard gauge railway in cooperation with the Saudi government.