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Whoa—-big story just posted by Washington Post reporters Lena Sun and Lyndsey Layton:

The train control system designed to prevent Metro crashes is malfunctioning across the railroad, suggesting that a technological failure at the heart of last month’s fatal crash may be widespread, according to officials and documents.

At least one-half dozen track circuits on four of the five lines of the transit system have failed to properly detect the presence of trains.

Six circuits have been shut down in addition to the one thought to have caused last month’s Red Line crash. Some of them—-including ‘circuits at Greenbelt on the Green Line, Grosvenor on the Red Line and Foggy Bottom on the Orange/Blue line’—-have been shut off, meaning trains can only pass through them one at a time, at 15 mph.

And double whoa:

[D]ocuments show that Metro technicians have detected malfunctions since at least July 11. Metro General Manager John B. Catoe Jr. said publicly as recently as July 16 that the agency has inspected all 3,000 circuits and not noted any problems.