Amtrak Prepares for Tunnel Boring Machine Launches for $6B Rail Replacement

Work continues on Amtrak’s largest-ever infrastructure investment — the roughly $6 billion B&P Tunnel Replacement Program in Baltimore, Maryland — as crews prepare to launch the first of two tunnel boring machines for the project in 2028.

Preparation work over the last year on the project, which will replace the 153-year-old Baltimore & Potomac Tunnel with two new passenger rail tunnels, has included:

• Excavation and construction of initial footings for the new Mulberry Street railroad bridge in Baltimore, which will be the first of five reconstructed for the project.
• More than halfway finished assembling the project’s first TBM.
• Progress on the 345-foot-long utility tunnel that, once finished next year, will carry water, sewer, communications and electrical utilities under the existing and future Northeast Corridor tracks.

Another accomplishment highlighted this year by Amtrak was the identification of several optimization opportunities surrounding the program by both Amtrak and the Federal Rail Administration, including:

• Eliminating the future Intermediate Ventilation Facility and its smaller connecting tunnel without impacting safety and operations.
• Raising the future tunnel’s vertical track alignment at its deepest point by 10-22 feet to reduce excavation needs and improve construction efficiency.
• Optimized systems and resequenced work activities for more efficient delivery.

Amtrak plans to open the new 2-mile tunnels, to be named after Frederick Douglass, in 2036. The first major contract for the project was awarded in late 2023, and utility excavation began in 2024.

Two of three contracts have been awarded for this project: 

• Package A – awarded to Kiewit-Shea Tunnel Contractors and covering the boring of the twin tunnels.
• Package B – awarded to the Clark Construction/Stacy and Witbeck Joint Venture and covering the construction of a new West Baltimore MARC Station, a new southern approach for that station and several bridge improvements.

Once complete, the B&P Tunnel Replacement Program will free up what Amtrak calls the most congested rail bottleneck south of New Jersey via two new tunnels for electrified Amtrak and MARC passenger trains. The final project will also deliver a new West Baltimore MARC Station, 10 miles of rail infrastructure upgrades and local street and bridge improvements.

The original 1.4-mile B&P Tunnel was opened in 1873 and represents the oldest Amtrak tunnel in existence. The tunnel’s tight curves limit train speeds to 30 mph, and the structure generates frequent delays and maintenance needs as it continues to age.