BNSF is happy to help restore an estuary at Lund’s Gulch, but it would cost the county $16 million.

MEADOWDALE — Snohomish County’s parks director calls it a once-in-a-lifetime opportunity.

BNSF Railway considers it a victory for its business and the public.

Together, they’re trying to drum up support for a project to remake the railroad tracks that since the late 19th century have largely cut off the mouth of a salmon-spawning stream from Puget Sound. By building a new five-span railroad bridge along the shore at Meadowdale Beach Park, they hope to return Lund’s Gulch Creek to something resembling its natural state.

“It’s kind of a once-in-a-generation, once-in-a-lifetime deal,” parks director Tom Teigen said.

The work would aim to create a more free-flowing estuary at the county park just north of Edmonds. A 90-foot-wide opening under the bridge would replace the existing hobbit-size tunnel that’s often closed off during the rainy season. That could open up salmon runs — and provide year-round access to the beach for all patrons. That includes people with disabilities who might find the current tunnel impossible to navigate, even under the best of conditions.

BNSF, which owns the tracks, strongly supports the idea. The railroad has offered to build the two-track railroad bridge. They’d like to get it done by the end of 2020.

“The proposed bridge will allow for the separation of the pedestrian walkway and channel, while also helping to restore a small estuary east of our mainline,” said Courtney Wallace, a railroad spokeswoman. “This project is a win for the county, the public, the railroad and the environment.”

There’s a catch: The county would have to pay for it. At up to $16 million, it won’t be cheap.

The county has been seeking state and federal grant money, said Logan Daniels, a county parks engineer and project manager. That’s in addition to approximately $2 million spent over the past few years on study and design.

U.S. Rep. Rick Larsen offered encouragement Tuesday when he toured the area for the first time.

“It’s a great project, mostly because everybody is on the same page,” Larsen said.

The congressman identified the Consolidated Rail Infrastructure and Safety Improvements Program, also known as a CRISI grant, as a potential federal funding source.

During the tour, Amtrak and freight trains whizzed by. The tracks sit atop a raised strip of rock and earth, roughly one story above the surrounding landscape. They’re blocked off by a chain-link fence and no-trespassing signs.

During construction, trains would be routed onto a temporary side track.

Several park supporters who live in the area joined the tour.

“It’s a gem in a very densely urban area,” said Barb Ingram, a neighbor who has helped guide the park’s development since the 1980s.

And, Ingram said, the county plan would make it better, both as a park and as natural habitat.

Joe Scordino, a retired fisheries biologist from the National Oceanic and Atmospheric Administration, knows the park well. He brings Meadowdale High School students there to teach them about fish habitat. They take water-quality samples and release thousands of salmon fry into the creek each year.

Endangered chinook don’t spawn there — they need large waterways like the Snohomish River, Scordino said. The species would benefit, he said, because juvenile fish could use the estuary for shelter. Lund’s Gulch also is home to chum and coho salmon, as well as cutthroat trout.

“This will be great,” he said. “One of the biggest problems for chinook salmon in Puget Sound is the near-shore environment.”

For now, bulkheads disrupt most of the natural shoreline habitat.

Meadowdale Beach Park borders the suburban street grid west of Lynnwood. The county bought the land in 1971 and opened it as a public park in 1988.

Lund’s Gulch runs through it, as a does a popular mile-and-a-half hiking trail. The park includes 108 acres, much of it second-growth forest. The city of Lynnwood owns more than 90 adjacent acres of open space.

Noah Haglund: 425-339-3465; nhaglund@herald net.com. Twitter: @NWhaglund.