Rapid Transit Experience with Chopper-Controlled DC Motor Propulsion

Bay Area Rapid Transit (BART) cars using solid-state choppers and regenerative braking have accumulated about 154 million car mi since 1972 and are adding about 28 million additional car mi/year. For the February 1978 to February 1979 year, the propulsion system mean time between failures (MTBF) was just over 500 h and contributed 37 percent of all vehicle failures. In the same period, the four-traction motor MTBF was 2174 h, which is more than twice its value of several years ago. Modifications currently planned or in progress are expected to increase the propulsion system MTBF to about 800 h by 1981.