New Jersey Transit’s board voted on Wednesday to allow the agency to lead the environmental study for a project to build a new train tunnel under the Hudson River, an important early step as officials move forward on the plans.

The environmental review could take two to three years and will be coordinated by New Jersey Transit but paid for by Amtrak, officials said. As part of a joint effort, Amtrak will soon begin preliminary engineering work for the tunnel project.

The move came five years after Gov. Chris Christie of New Jersey canceled an earlier project by New Jersey Transit to build a tunnel under the river. The new plan, which is part of an Amtrak proposal known as the Gateway project, gained momentum this summer and public support from Mr. Christie and Gov. Andrew M. Cuomo of New York.

At the New Jersey Transit board meeting on Wednesday in Newark, the board’s vice chairman, Bruce Meisel, called the vote “a step in the right direction.” He urged others at the meeting to continue to talk to local leaders from both parties about the importance of building a new tunnel.