A plan to replace the decrepit Baltimore & Potomac Tunnel in Maryland, which officials say is needed for safety reasons and to meet East Coast passenger and commercial rail needs, is moving forward after years of delays.

Amtrak and Maryland announced an agreement Friday on a $4 billion plan to build a replacement in the next decade. The railroad is completing the design and negotiating property acquisitions, while promising the tunnel will carry electric-powered trains to reduce environmental impacts on Baltimore neighborhoods along the new route.

The 148-year-old tunnel under West Baltimore is a major bottleneck for Amtrak, Maryland’s MARC commuter trains and commercial rail traffic that moves through the Northeast Corridor. The announcement comes as the nation debates funding for aging infrastructure amid new priorities in Washington that laud rail and alternate modes of transportation. Funding for the Baltimore project remains uncertain.

Trains slow to a crawling 30 mph in the two-track, 1.4-mile tunnel between Baltimore’s Penn Station and points south, creating delays up and down the corridor. The tunnel is the biggest chokepoint between Washington and New Jersey.

Amtrak said it plans to replace the post-Civil War-era tunnel with single-track twin tunnels that would arc about a half-mile north of the existing tunnel. Trains would travel up to 100 mph.

The proposal is a scaled-down version of a plan approved four years ago by the Federal Railroad Administration that called for four single-track tunnel tubes. Railroad officials say by building only two tunnels, the project will save $1 billion and up to two years on construction while still tripling train capacity to accommodate future demand. The additional two tunnels could be built in a second phase as funding becomes available, Amtrak said.

The proposal is dependent upon Amtrak securing federal and state funding. Amtrak has budgeted $65 million for design and preconstruction work in the next year, including negotiations to acquire more than three dozen properties, including 22 residential buildings, 13 businesses and four churches that would be demolished.

The passenger railroad also is seeking $257 million for the tunnel project this year from Congress.

“This is a critical project not just for Baltimore and the state of Maryland, but for the entire Northeast Corridor of the United States,” Maryland Gov. Larry Hogan (R) said Thursday night at a celebration in Baltimore of Amtrak’s five decades in operation. He said he directed state Transportation Secretary Gregory Slater to advance discussions with Amtrak on “an historic partnership” to replace the tunnel.

Amtrak on Friday also announced it will name the new tunnel after Maryland native and abolitionist Frederick Douglass, who was enslaved in Baltimore, where he learned to read and write before fleeing on a train to escape slavery. The old tunnel, which freight trains will continue to use, will keep its name.

The naming of the Douglass tunnel coincides with Juneteenth, a celebration of the date that the last enslaved African Americans were granted freedom. President Biden on Thursday established Juneteenth, which falls on June 19 each year, as a federal holiday.

One of the oldest structures in the Northeast rail corridor, the B&P tunnel is a crucial piece of the network connecting Washington to Boston, moving more than 259 million passengers each year. The project ranks near the top of Amtrak’s priority list.

The FRA has declared the tunnel structurally deficient, unable to meet projected demands and not suited for high-speed usage.

It has critical structural problems, including water issues and brick deterioration, according to a federal review of the project. Water-saturated soil beneath the tunnel is causing its floor slabs to sink, forcing Amtrak to make costly and repeated repairs. Amtrak spent $71 million last year to replace portions of the track in the tunnel, according to the railroad.

“The tunnel is the major source of delay MARC and Amtrak trains encounter,” said Jeffrey Ensor, who is leading the tunnel project at Amtrak.

The tunnel also requires frequent inspections and maintenance to keep operations safe, he said, noting it is at the end of its useful life.

Greg Regan, president of the Transportation Trades Department for the AFL-CIO, which represents Amtrak and MARC workers, said the tunnel conditions — and the accompanying travel delays and price tag for repairs — show why the nation should invest in infrastructure. It is telling, he said, that a structure built in 1873 is still in use.

“When you say 150 years, that is a long time. The idea that president [Ulysses S.] Grant was in office when this was created, I mean, that should be a pretty stark sort of wake-up call for people that we need to fix this,” he said. “We need to make this tunnel a priority.”

The FRA concluded in a 2017 report that replacing the tunnel within 10 to 20 years is critical, noting that in the long-term, “the frequency and magnitude of repairs required to maintain the existing B&P Tunnel is expected to increase.”

Under the Amtrak plan, it would take between 10 to 12 years to complete the tunnel if federal funds are made available. Amtrak’s timeline includes utility relocation and demolition next year, with excavation and more heavy construction in 2023.

Officials said construction is complicated by delicate crossover work with the operational railroad, as well as softening curves to allow for higher speeds. About 30,000 jobs would be created during construction.

The new route would stretch the two single-track tunnel tubes nearly four miles between Baltimore’s Penn Station and Gwynns Falls Bridge. The West Baltimore MARC station would be relocated. The project includes a high-capacity signal system that would allow trains to be spaced closer together and interlocking changes that would facilitate faster speeds out of Penn Station.

The changes would lead to savings of up to seven hours of daily rail delays and open the door for MARC express service between Baltimore and Washington in 30 minutes. The ride on Amtrak’s Acela train, which takes about 30 minutes, would be cut to 21 minutes.

The prospect of shorter trips will open opportunities for employment, economic development and greater access to affordable housing in the region, said Joe McAndrew, vice president of transportation at the Greater Washington Partnership, a group of corporate leaders pushing for improved transportation options across the greater Washington region.

“We can’t have a better-connected super region from Baltimore to Richmond without this tunnel,” McAndrew said. “We’ve got to make the right investments and really move to have a rapid regional rail system connecting our economic centers.”

The tunnel would only carry trains on electric power. Maryland officials said the state agreed to electrify all MARC trains by the time the tunnel would open in as early as 2032. MARC trains now run on diesel.

Keeping the new tunnel traffic on electric power assuages the biggest concern raised by communities along the new route. Residents opposed potential exposure to diesel train emissions through three ventilation facilities. The route would run beneath residential and historic neighborhoods that primarily are home to Black and lower-income residents.

“Switching trains from diesel to electric is good on a number of environmental fronts, and the new electrified operations for MARC also help us with train operations because those trains can accelerate faster, which helps us make better use of the railroad,” Ensor said.

Federal, state and local officials joined Amtrak leaders at the north portal of the tunnel Friday to mark the 150th anniversary of its groundbreaking and promote plans for growth. Several members of Maryland’s congressional delegation pledged to push for federal funding.

Baltimore officials said they are working with Amtrak to address residents’ concerns, but added that the city is onboard with the new plan, which they say will bring economic and transportation benefits. Amtrak has committed $50 million to invest in West Baltimore for parks and in creating economic and job-training opportunities.

“Baltimore is excited for the potential of the B&P Tunnel Replacement Program — not only for the jobs it can create during construction, but also for the new West Baltimore MARC Station and enhanced MARC service,” Mayor Brandon Scott (D) said in a statement. “Making the needed investments to improve the accessibility and usability of the MARC transportation system for our residents is the key to a safer, stronger, more vibrant Baltimore.”