As project leaders work with their contractor under a new agreement (pdf) to make the fixes and improvements necessary to open the Silver Line Metrorail through Tysons Corner to Reston, officials are assuring the public that ongoing problems with the Silver Line’s control system will not jeopardize their safety on the tracks.
As any Metro train makes its way from station to station to pick up commuters and tourists, its speed and spacing are controlled by a computer. The system that prevents it from blowing through red signals, going too fast, or colliding with a train in front is known as Automatic Train Control, or ATC.
Silver not agreeing with OrangeThe ATC system that will be used on the 11.5-mile Silver Line was built by the same firm whose name is all over Metro’s existing automated signaling system in use on more than 100 miles of track: Alstom Signaling, one of only a handful of companies qualified to perform such work.
The problems Alstom is now tasked with fixing are mostly connected to the new Silver Line not syncing with the old Orange Line, causing breaks in the communications link and thus slowing down smooth rail operations. Alstom is a subcontractor of Bechtel, the construction and engineering giant hired by the state of Virginia last decade to build the rail line. The project has since been in the hands of the Metropolitan Washington Airports Authority (MWAA).
“Train control systems are designed to fail safe,” said Pat Nowakowski, the project’s executive director at MWAA who will be leaving his post this week for a job with a yet-to-be announced public transit agency.
Unlike the 2009 Red Line crash (pdf), when the failure of Alstom’s circuit signals caused a deadly collision, the breakdowns in the Silver Line ATC system are causing test trains to stop in their tracks. The problem is they are stopping when they should not. In technical terms, the track circuits are "bobbing." . .Click here for the rest of this article and Di Caro's radio report.
Any article about the Silver Line that begins with a headline that "Project leaders assure..." has to be automatically suspect. How many times have we been assured the project was on schedule, under budget, the problems would be fixed on time, etc? "Project leaders" really have no credibility at this point.