The century-old railroad bridge spanning Salmon Bay near the Ballard Locks is nearing the end of its life, and plans are underway to replace the iconic structure.

The bascule-style, or “jackknife” bridge was built in 1912, with what was then brand new technology. But, it had a fatal flaw, according to Courtney Wallace from BNSF Railway.

“As it goes up and down with a counterweight, what we found was that the trunion bearing was getting fatigued,” Wallace told My Ballard. Trunion bearings are what allow the bridge to raise and lower, so the flaw resulted in the bridge being stuck open for six months in 1948 (photo below). Luckily, back then there was another railroad bridge east of the Ballard Bridge used by another railroad, Northern Pacific. That bridge was demolished in 1976, and the rail line eventually became the Burke-Gilman Trail.

Roughly 10 years ago, BNSF replaced the trunion bearings because workers heard some popping noises on the bridge. At that time, they predicted they had maybe two decades before having to address the issue again.

“Unfortunately, we’re starting to hear those popping sounds again, and dealing with more maintenance issues. So, we could replace the trunion bearings, but it’s going to be the same issue,” Wallace said. “Eventually that bridge is going to get stuck. It’s either going to get stuck in the ‘up’ position, which will impact freight traffic, or it gets stuck in the ‘down’ position, and boats going through the locks can’t pass through.” The bridge carries 30-40 passenger and freight trains each day.

BNSF is in an information gathering phase, getting input from the maritime community about the design of the bridge. They’re proposing a vertical-lift bridge, much like what spans the Willamette River in Portland. BNSF is proposing that the Salmon Bay bridge have 155 feet of vertical clearance to allow for tall ships to pass through.

The proposal will go through the federal permitting process, with the US Coast Guard and Army Corps of Engineers as the lead agencies for the project. Wallace says the permitting phase will likely take at least two years, and if approved, construction will start alongside the current bridge, 50 feet to the west. She estimates construction would take three years, during which the old bridge would stay open. BNSF will do as much of the construction by water as possible, using barges to eliminate truck traffic. Once the new bridge is up and running, they’ll work on removing the old bridge.

Wallace says feedback from the maritime community so far has been positive. “Most folks understand the need to replace the bridge.” BNSF also plans to hold public meetings so community members can learn about the project and weigh in before they start the permitting process next year.

The bridge construction would be funded by BNSF — they expect it to cost $200 million.

Historic photos courtesy BNSF