A planned $11 billion rail tunnel seen as a key to train travel up and down the northeastern U.S. received a boost Friday with a crucial, and long sought, federal environmental approval.

The record of decision announced by the Department of Transportation means the project to build a new Hudson River tunnel connecting New York and New Jersey can push ahead with engineering and design work. The DOT's approval also is expected to smooth the way toward the awarding of federal grants the project needs to begin construction.

What You Need To Know

  • The project had been waiting three years since it completed its environmental studies

  • The existing tunnel is more than 110 years old and prone to problems and delays

  • The tunnel, part of the broader Gateway project to expand rail capacity in the New York region, dates back roughly 10 years

  •  Stakeholders, including Democratic New York Gov. Andrew Cuomo, have alleged the Trump administration delayed the approval for political reasons

The tunnel, part of the broader Gateway project to expand rail capacity in the New York region, dates back roughly 10 years and completed environmental studies three years ago. Stakeholders, including Democratic New York Gov. Andrew Cuomo, have alleged the Trump administration delayed the approval for political reasons, a charge Trump’s administration denied.

“This is a big step for the Northeast, and for the entire country, as these tunnels connect so many people, jobs, and businesses," Transportation Secretary Pete Buttigieg said in a statement. Now we need to make sure to provide the funding America needs to deliver world-leading infrastructure in this region and in every part of the country.”

New Jersey Gov. Phil Murphy called it “a significant milestone.”

The existing tunnel is more than 110 years old and prone to problems and delays due to crumbling walls and aging signals and wiring. Saltwater intrusion from Superstorm Sandy in 2012 accelerated the tunnel's deterioration and forced Amtrak, which owns the tunnel, to embark on costly repairs to keep the tunnel functioning reliably.

Hundreds of trains and hundreds of thousands of passengers pass through the tunnel per day during normal times, and delays can ripple up and down the East Coast between Boston and Washington, D.C. Once primary construction begins, the tunnel could take as long as six or seven years to complete.

Under the Gateway project, the new tunnel would be built parallel to the existing tunnel. Once completed, the existing tunnel would be taken out of service for a complete overhaul, estimated to take as long as two years. A plan to add tracks in New York's Penn Station to accommodate more trains when both tunnels are in service is in the early stages.