B&P Tunnel Replacement Program

The Baltimore & Potomac (B&P) Tunnel Replacement Program is modernizing the 1.4-mile tunnel connecting Baltimore's Penn Station to Washington, D.C., and reconstructing six miles of dedicated guideway south of the station. The program addresses significant safety issues and deterioration through construction of two new tunnel tubes, roadway and railroad bridges, rail systems, track, and supporting railroad infrastructure, along with a new ADA-accessible West Baltimore MARC Station. 

The South Approach constructs a new rail alignment into the southern portal of the new tunnels. Though most of the work is within one mile of the portal, the project footprint extends approximately 10 miles, with a portion supporting train speeds up to 125 mph. 

Need 

Built over 150 years ago, the B&P Tunnel is the oldest in Amtrak's system and limits operational efficiency, requiring significant modernization. Located in the busy Northeast Corridor with around 130 trains passing through daily, the tunnel's age and tight curvature force trains to slow to 30 mph, creating a major bottleneck in the country's most heavily used passenger rail corridor. 

The project smooths and widens the tunnel's curvature to alleviate these issues, while also allowing modern fire and life safety systems to be updated without the need for excessive and costly maintenance. 

The South Approach connects the new tunnels, strengthens the surrounding rail network, improves accessibility, and supports safer, more reliable passenger and freight service throughout the corridor. 

Work

• Construct two new tunnel tubes and a 14-foot-wide utility tunnel beneath active tracks 
• Install 13 miles of track and seven crossovers 
• Replace five bridges and build a concrete retaining structure up to 50 feet deep, 100 feet wide, and 2,000 feet long to facilitate the descent into the new tunnels 
• Reconstruct the West Baltimore MARC commuter rail station 
• Reconfigure city street alignments and major utility infrastructure 
• Replace three route miles of four-track catenary systems supporting 138 kV transmission lines and signal power 

Collaboration 

The B&P Tunnel Replacement Program is delivered through a joint venture between Clark Construction and Stacy Witbeck, with the WSP/Parsons Joint Venture serving as designer.