SEATTLE — Editor's note: The above video from April follows city leaders calling for underground light rail to West Seattle.

Boring a tunnel under Salmon Bay to bring light rail to Seattle's Ballard neighborhood would up the price of the extension by an estimated $450 million more than the voter-approved plan. 

An option studied by Sound Transit would take light rail from the proposed Interbay station near West Dravus Street, crossing over BNSF tracks, descending into a tunnel beneath Salmon Bay and terminating at a tunnel station beneath 20th Avenue NW near NW Market Street in Ballard. 

Tunnel options 2
Sound Transit

It's cheaper than the previous design, which would have brought the rail line north of Fishermen's Terminal before dipping under Salmon Bay. That would cost an estimated $750 million.

Tunnel option
Sound Transit

A tunnel route would still require third-party funding.

However, it's $350 million more than the option that would build an elevated line over Salmon Bay. In that scenario, the light rail would emerge from the downtown tunnel east of the BNSF railroad tracks to a Smith Cove station between West Galer Street and the Magnolia bridges. An Interbay station could be on Thorndyke Avenue West north of West Dravus Street. 

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From there, the preferred line without third-party funding would cross Salmon Bay on a fixed bridge near the Ballard Bridge and continue to Ballard station on 14th Avenue Northwest via an elevated railway. The Ballard station would be located on Northwest Market Street. 

Elevated option
Sound Transit

Sound Transit leaders have said that without additional funding, elevated light rail to Ballard and West Seattle is preferred. 

In April, a group of elected leaders, including Seattle Mayor Jenny Durkan, King County Executive Dow Constantine and several city council members, signaled broad support for the tunnel option to Ballard and West Seattle. 

The Ballard and West Seattle projects will add 11.8 miles of light rail and are expected to open in 2035 and 2030, respectively.