JOHN DALTON, the man who steered the very challenging Green Line extension to the finish line in Boston, is taking his talents to New York City and one of the biggest and most important infrastructure projects in the country.

Dalton has been named senior project director for the Gateway Trans-Hudson Partnership, which seeks to build a new 10-mile, two-track tunnel from Penn Station in Manhattan to Newark, New Jersey, underneath the Hudson River. The project also calls for refurbishing the existing old and storm-damaged tunnel that already runs under the river.

The 10-mile stretch is currently the most vulnerable section of the rail corridor that runs from Boston to Washington, DC, carrying roughly 200,000 Amtrak and New Jersey Transit passengers a day. “It is really kind of a choke point for Amtrak,” Dalton said.

T officials had long hoped they could keep Dalton at the transit authority. He was recruited from a job in Chicago at a time when there was great skepticism about the T’s ability to complete large projects. The cost of extending the Green Line from Lechmere to Somerville and Medford had ballooned from $2 billion to more than $3 billion and there was talk of just canceling the project. Instead, the project was pared back to $2.3 billion, with Somerville and Cambridge stepping forward to chip in $70 million.

Dalton recruited a team of employees to oversee the project and guided it to completion despite COVID and countless construction challenges. There were some delays, but the project stayed within its budget – the money from Somerville and Cambridge ended up not being needed.

Dalton made no secret of his desire to stay in Massachusetts, but none of the big projects on the horizon (the I-90 Allston project, the Cape Cod bridges, or the Red-Blue subway connector) were anywhere near ready to go. So Dalton looked elsewhere, and ended up as a senior vice president at STV, a professional services firm that plans, designs, and manages infrastructure projects across North America.

His title is senior project director on the Gateway project, leading a team of consultants building the new Hudson tunnel. In a telephone interview, he was plotting out the staging of the roughly $16 billion project and explaining how a tunnel under the Hudson would get built. (He sounded a lot like US Rep. Seth Moulton, who has argued that building a tunnel rail link connecting North and South stations in Boston would be no big deal.)

Dalton said he intends to continue living in the Boston area, commuting to New York for the new job, while his son finishes high school.

As far as the project goes, a truly game-changing project important to this part of the country, I couldn’t say no,” he said. “It’s what I do.”