The federal funding commitment is the second largest award in the country and the largest west of the Hudson River.

It means the VTA has secured nearly all the funding required for the US$12.7bn project. Over the next 60 days, the VTA will define the funding gap and work with the FTA to identify ways to ensure the project’s long-term success.

VTA general manager and CEO Carolyn Gonot said the federal commitment had greatly advanced the funding plan, but there was still a critical hole to fill. “

“We want to thank the FTA for their trust in the programme’s planning and in VTA’s ability to deliver it through this major award of US$5.1bn. VTA is fully committed to advancing the programme into engineering and applying for a Full Funding Grant Agreement at the appropriate time,” she said.

VTA’s extension of the regional BART system is the largest transport infrastructure project in Santa Clara County’s history.

Last month the construction phase was officially launched with a groundbreaking ceremony on the site of what will be the West Portal. From there the TBM will be launched to build the 8km tunnel from Santa Clara and through downtown San José.