Unusual events caused Seattle monorail fire

An unusual and complicated sequence of events, all over in about one minute, caused the Seattle monorail fire May 31, Seattle Center and Seattle Monorail Services officials said yesterday.

The fire, the first in the Seattle monorail's 42-year history, stranded and forced the evacuation of about 150 riders and closed the line indefinitely. A free shuttle service has been operating in its place between Seattle Center and Westlake Center.

Tom Albro, director of Seattle Monorail Services, said the fire was caused by "a mechanical failure that, through an extraordinary set of events, led to an electrical short."

The fire occurred about 5:20 p.m. on Memorial Day, when a low-speed drive shaft on the southbound Blue Train broke, causing a nearby high-speed shaft to rotate faster.

"It started really revving up," Albro said.

This caused the high-speed shaft to break, too.

A piece of that shaft broke free and smashed into the housing around another part of the train.

Officials said a low-speed shaft failure is not unheard of, but a breakdown of a high-speed shaft is highly unusual. After the piece of the shaft crashed into the housing, sparks flew.

"It changed the air to an ionized air, just like happens in lightning," said Virginia Anderson, director of Seattle Center.

The driver stopped the train, but the ionized air created a short circuit between the positive and negative rails, officials said. The flurry of sparks ignited the tires and other parts, starting the fire. The system's circuit breakers then tripped and, at about 5:21 p.m., cut off all power.

Officials yesterday declined to say when the monorail would reopen or when an investigation by two outside firms would be complete. "Our objective is to resume full service at the earliest possible date that we can do it safely," Albro said.

During a typical July, the monorail carries about 400,000 people, officials said. The shuttle service is far less popular: Officials estimated it will provide fewer than 100,000 rides this month.

The decrease in ridership has affected business in Seattle Center and Westlake Center, although Seattle Center has fared better than was expected.

"We are experiencing some decline," Anderson said. "From our perspective, it's not been as dramatic as we might have thought. I think for Westlake it might be a little bit more dramatic."

Judy Burnside, manager of the Westlake Center Made in Washington store, said her shop is seeing about one-quarter fewer customers since the beginning of June.

Matthew Rodriguez: 206-464-3192