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The Washington Post reports that last month’s DC Metro crash was attributed to a “freak occurrence” that Metro officials had never heard of. However, the occurrence is familiar to experts.
Federal investigators have determined that the the track circuit where the crash occurred intermittently lost its ability to detect a train. The failure would not be obvious in the Metro’s operations center, as the circuit “flickered” from operational to not.
While the issue was unknown to Metro experts, Ron Tolmei, an electrical engineer and former manager of research and development at BART(Bay Area Rapid Transit), said he was aware of intermittent failure of track circuits on both the BART and the Muni light rail systems in San Francisco. Shortly after BART opened in 1972, it installed a backup system to prevent this after tests revealed that on several occasions, the system failed to detect a train in some instances. The system does not allow a block that was previously occupied to be cleared until the next sequential block in a train’s path is detected.
We have no doubt some system will be installed on the Metro after this point. What surprises us is that Metro officials are admitting they never even heard of such a thing. How could that be? The BART and the Metro were built similarly in about the same time period, thus sharing many features. Even without that, shouldn’t a transit system have some experts onboard, or on retainer who were and recommended such a system be implemented? We will await more of the investigation to find out.
