Sound Transit, a US public transit agency serving the Seattle metropolitan area, has commenced construction of the 13.7km-long Lynnwood Link Extension of the light rail network.

The extension will extend the existing infrastructure from Northgate to Lynnwood City Center in Seattle, Washington.

As part of the plan, four new stations will be constructed in Lynnwood, Shoreline, Mountlake Terrace and Seattle.

The total cost of the project is estimated to be $2.9bn, of which $1.17bn will come from the Funding Grant Agreement executed by the Federal Transit Administration (FTA).

US DoT Build America Bureau has also issued a loan of $658m with a low-interest rate for the project.

Sound Transit CEO Peter Rogoff said: “From the beginning, this project has received enthusiastic support from the federal, state and local governments, our congressional delegation, the business and labour communities, and voters, a sign of the hunger for relief from the horrendous highway congestion facing travellers every day.

“This project will be a game changer for Snohomish County commuters, and in the years to come, we will be extending Link from Lynnwood all the way to Everett.”

The line is expected to become operational by 2024 and Sound Transit intends to operate trains every four to six minutes at peak weekday hours.

In June, Sound Transit received the first of 152 previously ordered LRVs at its Link Operations and Maintenance Facility in Seattle, which will be operated on the new line.

By 2026, the new line is estimated to carry around 47,000 to 55,000 passengers daily.

In July, Sound Transit selected a joint venture (JV) comprising Stacy and Witbeck and construction company Kuney to build the Downtown Redmond Link Extension.