Trackside Classics: The Budd RDC – Self-Propelled Railcars To The Rescue


(first posted 11/18/2016)     The postwar era presented America’s railroads with a dilemma.  Wartime traffic swelled profits but wore out prewar equipment.  But faced with new cars, new roads, unlimited gas and tires, and thousands of cheap war surplus transport planes, ICC-mandated passenger service, became a profit drain.  New equipment was needed, but so were new ideas.  Nowhere was this more apparent than on lightly used branch line and commuter services.

The folks at the Edward G. Budd manufacturing company thought they had the answer to restore traffic and profits: The Budd Rail Diesel Car (RDC).  While that thesis didn’t really pan out, the RDC itself proved to be reliable, flexible and incredibly long-lived, and remained a key part of America’s passenger rail fleet through the CC era.


The RDC was a concept with a rich ancestry.  As soon as large internal combustion gasoline engines were perfected around the turn of the 20th century, people began to combine them with a railroad passenger or combine car body to provide self-propelled service overly lightly-traveled branch lines.  The porthole-windowed, prow-shaped McKeen Motor Car was the first successful example, entering service in 1905.

These cars used a marine-type gas engine mounted in the power truck, driving one axle through a direct mechanical drive. Problems with that drive train, including reversing (the camshaft had to be switched to run the engine backwards), and clutches failing were a major limitation in these cars, and were a spur to developing gas-electric and hydraulic drive alternatives.

MW 31 ASME Dedication, 8-16-03. Bill Buhrmaster photo.

Over time, the rail motor car, as it became known, improved, with more substantial bodies and more powerful engines.  Many of the bodies were made by street- and interurban car builders like St. Louis Car, with engines from Winton Motors in Cleveland.  Winton, an automotive pioneer, had long abandoned that market to specialize in large gasoline and, starting in the late 20s, diesel engines.  With the success of rail motor cars and the rise of diesel electric locomotives, business took off, the company renamed itself Electro Motive Corporation, and soon became the Electro Motive Division (EMD) of General Motors.


Meanwhile, in Philadelphia, auto body builder Edward G. Budd was getting into the rail business with a revolutionary idea – car bodies made lighter, stronger, and longer lasting due to a structural covering of corrugated stainless steel.  The key was Budd’s shotweld process, which eliminated the rows of rivets then common on passenger cars.  From the landmark Pioneer Zephyr of 1934, Budd took a growing share of the passenger car market.


By the the late ’40s Edward Budd was gone, but his company was still looking for new opportunities.  They found one by marrying Budd’s shotwelded carbody to an underfloor pair of 6-cylinder, 275hp Detroit Diesel Series 110 engines and power trucks, and introduced the Budd Rail Diesel Car in 1949. Each engine drove an axle through a hydraulic torque converter derived from the M46 Patton tank. Multiple RDC cars could be coupled together to form a self propelled train.


Stylistically,  it was a perfect complement to the long-distance streamliners, with well-resolved cab ends and a well integrated roof bulge that housed the engines’ intake and exhaust fans, connected by ducts that served as interior dividers.  Interiors were simple and modern, with reversible seats and stainless steel package racks.


From 1949 through 1962, Budd produced 398 RDC cars.  The vast majority were 85-foot RDC-1 coaches, but the RDC was also available as an RDC-2 coach/baggage combine, an RDC-3 coach/baggage/Railroad Post Office car, a short, 74-foot RDC-4 baggage/RPO, and an RDC-9 trailer with higher seating and no control cab. While some RDCs plied lightly traveled branch routes, many wound up in commuter service, with Boston and Maine acquiring 108 cars for that service.  Other big users were the Pennsylvania-Reading Seashore Lines, the New York Central, the New Haven, the Canadian Pacific and the B&O railroad.


B&O also offered the most unique RDC service, the 1956-63 Speedliner that connected New York (later cut back to Washington) and Pittsburgh.  The Speedliner was a 3 car train combining two RDC-1 coaches with a unique Baggage-Diner-Coach combine.  The menu was limited but the cooking was fresh and just as good as the Capitol Limited, considered the gold standard for railway dining.  (This image shows the Speedliner’s combine in later commuter service in Pittsburgh)


The 1950s was a big time for passenger train innovation, especially lightweight trains that could cover medium distance routes at lower costs.  New York Central had its Train X, General Motors adapted bus parts to create the Aero Train, and the New Haven turned to Budd for a sort of super-RDC train, the Roger Williams.  Made up of six RDC coaches with modified sheathing, it featured diesel-like cabs front and back, and served on medium distance runs.


Then there was the jet.  Meet the M-497.  Cobbled up by New York Central engineers to test the effects of high-speed – and very straight, well-maintained rails, it featured a pai of J-47 booster jets from a B-36 strapped to the top of an RDC with a streamlined front and rear.  The motors were removed, and on July 23rd, 1966 it hit a top speed of 183.68mph – an American record that still stands. Unfortunately, like the Central, the M-497 went nowhere fast: stripped of its jets, it finished out its days in commuter service.


Budd tried one last hurrah with the SPV-2000, a self-propelled Amfleet coach – a design derived from the high speed Metroliner cars of the late 60s.  Amtrak and Metro-North used them briefly for branch runs, but unlike their inspiration, they proved unreliable.

Ultimately, the RDC couldn’t stem the tide away from trains to cars and planes.  But the bodies were strong and the Detroit Diesels were unbreakable, so they soldiered on in commuter service well into the 1980s, and as de-motored coaches even longer.  The RDC didn’t save railroading, but it did its job well.  Which I can personally attest, having spent many days in the early ’70s riding in the cab of a B&O RDC traveling from McKeesport to Pittsburgh for an afternoon’s shopping.  Followed by dinner at Stouffer’s, another long-gone hallmark of mid-century optimism.