After the deadly train collision in D.C., SEPTA decided to inspect the train-control signals on the Market-Frankford Line in Philadelphia, since the signals were made by the same company that made those on the Metro in Washington.
The signals on the Market-Frankford Line were made by Alstom S.A., a large French manufacturer of transportation equipment and power plants.
"Last month, the equipment did not detect trains along one section of Boston's Orange Line. Engineers discovered the problem and immediately stopped using the automated system while they checked all circuits. Trains were dispatched by radio for 12 days, and MBTA personnel were posted at each station to give the go-ahead for trains to proceed, an MBTA spokesman told the Washington Post."