Sonoma-Marin Area Rail Transit officials intend to buy a used drawbridge in Galveston, Texas, to replace the 109-year-old swing bridge over the Petaluma River.
Rather than launch a $20 million rehab of the aging structure at Haystack Landing, and then perhaps spending $30 million to replace it in 20 years, SMART says that for $20 million it can buy and install the used bridge and have it last 75 to 80 years.
“I was looking for a different solution than retrofitting it,” said Farhad Mansourian, SMART's general manager.
SMART says it will have daily commute rail service on the line within four years.
The Texas bridge is on the BSFN Railway line linking the Texas mainland to Galveston Island. It was built in 1985 and is being replaced by a new vertical lift bridge to increase the channel width.
“It is a really solid bridge,” said Bill Gamlen, SMART chief engineer. “We will have to do some mechanical upgrades, but it is a very stout bridge. The BNSF doesn't want to get rid of it, but the Coast Guard is driving the replacement.”
It is called a bascule drawbridge, meaning it uses a counterweight to lift the “leaf,” or rail bed, into an almost vertical position. It is on the historic vehicle causeway that was converted to a rail line.
Gamlen said the new bridge would open or close in about 90 seconds, instead of the 2 to 3 minutes needed for the swing bridge.
It also is long enough to allow the Petaluma River channel to be widened from 56 feet to 87 feet, and allow SMART trains to cross at higher speeds.
The bridge over the Petaluma River was built in 1903. It uses a 5-horsepower electric motor, fabric belts and bevel gears to pivot slowly on a turntable that is 10 feet in diameter.
“One of the problems with the swing bridge is the reliability,” Gamlen said. “I have been out there and have seen it take three or four tries to get it closed.”