Results tagged “trackcircuit”

Ongoing track circuit repairs on the Red Line and scheduled maintenance on the Blue, Orange and Yellow Lines this weekend will lead to delays across the Metrorail system. Here's the details:

The larger Examiner enterprise may be pushing its online platform hot and heavy, but the local D.C. Examiner newspaper's ability to integrate its stories on the web still leaves a whole lot to be desired. Take this story from this morning, with the headline: "Metro builds Web site about faulty track circuits." You might expect to click through to the story and find contained therein the url, and maybe even (don't get too radical now) a hyperlink to the web site that is the entire subject of this story. But no. Nowhere within the version of this story posted online do you find a single hint as to where you might find the actual web site it's talking about. The editorial decision making process here is just bizarre.

The National Transportation Safety Board has put up a second advisory today on its web site regarding the most recent findings of its investigation of the June 22 Red Line crash. In it, we learn for the first time that the train control system track circuit where the accident occurred -- the same one that investigators initially found to be not functioning properly after testing it during the first couple of days after the crash -- was replaced by WMATA maintenance crews on June 17, five days before the accident. From the advisory:

After a post- accident review of recorded track circuit data, WMATA reported to the NTSB that the track circuit periodically lost its ability to detect trains after June 17th; the NTSB is reviewing documentation on the performance of that track circuit both before and after the June 17th replacement.

No conclusions from NTSB on this yet, of course, but given the timeline and the recorded data they mention, it certainly suggests the strong possibility that this was a faulty circuit which failed almost immediately after it was installed.