Amtrak advances optimized B&P Tunnel replacement program

Amtrak is advancing major construction activities for the Baltimore and Potomac Tunnel replacement program on the Northeast Corridor (NEC).

The existing 1.4-mile B&P Tunnel is the oldest Amtrak tunnel, having opened in 1873, and age-related issues lead to frequent delays and extensive maintenance needs, Amtrak officials said in a press release. The tunnel is at capacity and limits train speeds to 30 mph.

The replacement program calls for boring two new tunnels for electrified Amtrak and Maryland Area Regional Commuter (MARC) service. Amtrak's tunneling contractor is now ramping up preparatory work to launch the first of two tunnel boring machines in 2028.

Following more than a year of evaluations, Amtrak and the Federal Railroad Administration have identified several opportunities to optimize the replacement program design, improve constructability and scheduling, and address cost pressures, said Amtrak officials.

Planned optimizations include elimination of the intermediate ventilation facility and its smaller connecting tunnel; raising the future tunnel's vertical track alignment at its deepest point by about 10 feet; and optimizing and resequencing work activities for more efficient delivery, said Amtrak officials.

Concurrently, Amtrak has began preparations for the realignment of the NEC south of the future tunnels. Over the past year, Amtrak and its contractors have advanced excavation and construction for the new Mulberry Street bridge; reached the half-way point in manufacturing the first tunnel boring machine; and reached a milestone in the construction of a new utility tunnel that runs under the NEC.