Downtown bus-tunnel closure to continue through Friday

The downtown Seattle bus tunnel will remain closed through Friday, while technicians grapple with a computer glitch in the emergency safety system.

All 18 routes that use the tunnel are now operating on the streets.

No serious delays were reported by Wednesday afternoon, said Kevin Desmond, general manager for King County Metro Transit.

The computer system, installed this year, is designed to let operators control signals, ventilation, elevators, security cameras and lights from Metro's control center near Safeco Field in the event of an emergency. This week, the connection worked intermittently, officials said.

Metro closed the tunnel Monday, reopened it Tuesday, then closed it again at 5 a.m. Wednesday.

Sound Transit, which recently led a tunnel-retrofit project, found suspected flaws in two or three circuit boards and will also replace five or six similar boards, said its light-rail director, Ahmad Fazel. Replacement boards were being flown to Seattle Wednesday night, he said.

"The situation is unacceptable, and the work we're doing now with our contractors is to make sure the fix we put in place sticks, and we won't be back here in a day or two — or even a month or two," said Sound Transit spokesman Bruce Gray.

Fazel said the Seattle tunnel controls include a backup mode. But, he said, the flawed circuit boards were staying "on" even after they failed, disrupting the backup program, he said. Manual controls exist at each of the tunnel's five stations, but without the computer system, the stations would not be united, he said.

The system is part of a $39 million network supplied by GE Transportation Systems Global Signaling, for Sound Transit's 16-mile, $2.7 billion light-rail line to Seattle-Tacoma International Airport. Trains will share the tunnel with buses starting in late 2009.

Sound Transit recently celebrated the tunnel's reopening Sept. 24, after a two-year project to install new pavement and rails.

"This effort has included three months of testing of all the electrical and mechanical components, individually and as an integrated system," said chief executive officer Joni Earl.

Transit officials felt enormous pressure to finish on time, said John Niles, a leading Seattle light-rail critic.

Asked if the tunnel restarted prematurely, Fazel replied, "absolutely not," given the extent of the tests.

A permit from the Seattle Fire Department requires buses to go to the street if emergency systems in the tunnel aren't working, Fazel said. If that occurs after light-rail service begins, he said, trains would stop and change direction south of the tunnel, at the sports stadiums.

Mike Lindblom: 206-515-5631 or mlindblom@seattletimes.com