TR NEWS 286 MAY–JUNE 2013 11

PHOTO: THOMAS C. CORNILLIE PHOTO: K.WATA, WIKIMEDIA COMMONS TRB meetings and publications have provided forums TRB meetings and publications have provided The Denton County Transportation Authority operates DMU The Denton County Transportation and a connection with the vehicles between Denton, , System at Carrolton. Couplings that Dallas Area Rapid Transit into a single consolidate power and control connections designs— couple—a standard feature on current DMU demand. facilitate adapting configuration to ridership the intent of FRA crashworthiness regulations, coupled the intent of FRA crashworthiness regulations, door in Ameri- with regulatory reforms, has opened the proven can and Canadian cities to DMUs incorporating of these Asian and European designs. Implementation and pro- vehicles realizes long-sought cost efficiencies boarding, vides other improvements, such as low-floor accessibility. which reduces dwell times and improves and major for sharing news about emerging technologies needs, identifying trends and for articulating research the . applications for DMU technology in and its Self- Committee Through TRB’s research into the eco- Subcommittee, Powered Vehicle nomic characteristics of DMU operations and technology innovations continue to be discussed and shared. A DMU at an East Japan Railway Company station in Hitachiomiya, Japan. DMUs provide a large share of and commuter rail services in Japan. THOMAS C. CORNILLIE Research Overcomes Barriers Overcomes Research esigners of railroad vehicles long have recognized esigners of railroad the efficiencies achievable by locating propulsion achievable the efficiencies Realizing the Potential of Diesel Multiple-Unit Technology Diesel Multiple-Unit of the Potential Realizing For the past 60 years, the rail diesel (RDC) has epit- For the past 60 years, the rail diesel car transit As federal policy structures for supporting to advance. In other nations, DMU designs continued This situation changed with a confluence of research of CEM in meeting Research proving the effectiveness within a passenger-carrying vehicle, eliminating the need within a passenger-carrying Although various designs of for a separate . steam- and gasoline-fueled engines vehicles powered by in the 1890s, “diesel multiple came into service starting as a term-of-art in the late 1930s to unit” (DMU) emerged could operate as single or be describe vehicles that longer train. combined to form a The Budd omized DMU technology in North America. RDCs between Company of Philadelphia built nearly 400 a reputation for 1949 and 1962. These cars quickly gained a range of services, and for for adaptability to reliability, upgrades. the ease of making incremental technological DMU technology investments solidified in the 1970s, rail of commuter a way to improve the efficiency offered of European service. Revenue service demonstrations funding; however, DMUs were carried out with federal did not lead to the deployment of new tech- these efforts in 1979, the released Moreover, nology. but the SPV-2000, an updated version of the RDC, dubbed reputation lim- few orders and a checkered mechanical market. role in the North American ited the model’s were providing the DMUs By the turn of the 21st century, commuter rail ser- majority of nonelectrified intercity and of passenger ser- vices in Britain, and a significant portion in Japan. Certain vices across continental Europe and Federal Railroad Administration (FRA) regulations affect- slowed ing North American design practices, however, to import internationally developed vehicle efforts designs. Center Volpe by the U.S. Department of Transportation’s using FRA funding, with input from the American Public Passenger Rail Equipment Association’s Transportation Safety Standards task force and with updated research Salient in into the relative economies of DMU technology. was the consideration of crash energy man- these efforts agement (CEM) technologies, a standard in DMU vehicle designs in international applications. The author is Principal, Thomas Cornillie Independent of the Research Alameda, California, and Chair Scholar, Subcommittee of the TRB Commuter Rail Committee. D 00_TRN_286_TRN_286 7/11/13 5:04 PM Page 11 Page PM 5:04 7/11/13 00_TRN_286_TRN_286