Amtrak has announced further progress on the Baltimore and Potomac (B&P) Tunnel Replacement Program ahead of tunnel boring operations, which are scheduled to begin in 2028.
Working alongside the US Federal Railroad Administration (FRA), Amtrak has also identified a series of design and construction changes intended to improve the project’s efficiency, reduce costs and simplify delivery while maintaining safety and operational requirements.
The programme will replace the existing 1.4-mile B&P Tunnel, which opened in 1873 and carries Amtrak and MARC passenger services on the Northeast Corridor between Washington, D.C. and Baltimore. The ageing tunnel currently represents a significant operational constraint, with speed restrictions of up to 30 mph and ongoing maintenance requirements.
Preparatory construction has continued since the first major contract was awarded in late 2023, with utility relocation work beginning the following year.
Recent milestones include excavation and foundation works for the replacement of the Mulberry Street rail bridge, the first of five bridges to be reconstructed as part of the programme. Manufacturing of the two tunnel boring machines is also progressing, with the first machine now reported to be more than halfway through production.
Construction has also advanced on a 345-foot utility tunnel, which will carry water, sewer, electrical and communications services beneath both the existing railway and the future tunnel alignment. The structure is expected to be completed in 2027.
Following a year of engineering assessments, Amtrak and the FRA have agreed a number of modifications intended to reduce construction complexity and manage rising project costs.
These include removing the planned intermediate ventilation facility and its connecting tunnel after concluding that the change would not affect tunnel safety or railway operations. The revised design is also expected to reduce construction impacts on surrounding communities.
The tunnel alignment will also be raised by between 10 and 22 feet at its deepest section, reducing excavation requirements while maintaining a maximum depth of around 150 feet below street level. Amtrak and the FRA also plan to optimise construction sequencing, allowing more activities to be undertaken in parallel where practical.
Amtrak President Roger Harris said:Replacing the 153-year-old B&P Tunnel is critical to improving safety and reliability along the Northeast Corridor, America’s busiest passenger railroad. Thanks to a strong partnership with Administrator Fink and the entire FRA team, this investment is advancing with a clear path forward as we work toward opening the new Frederick Douglass Tunnel in 2036. Successful delivery of this program will continue to rely on support and collaboration from all our partners to address and mitigate current and future challenges.
The completed programme will provide two new electrified tunnel bores for Amtrak and MARC passenger services, alongside a new accessible West Baltimore MARC station, approximately 10 miles of associated railway infrastructure improvements, and upgrades to local roads and bridges.
