The need to replace the Baltimore & Potomac Tunnel that winds its way beneath West Baltimore became evident once again this week, as crews descended on a portion of the nearly 150-year-old rail bore to conduct emergency track work.
According to Amtrak, which owns the tunnel and is conducting the work, the issue — which forced the Maryland Transit Administration to announce likely delays for MARC commuter rail passengers this week — is a symptom of a long-standing problem.
"The tunnel has a concrete floor that has been plagued with localized settlement over the past several years due to erosion of the underlying soil from excessive water infiltration into the tunnel," said Christina Leeds, a spokeswoman, in an email.
The tunnel — and options for its replacement — are the subject of an ongoing engineering and environmental study being conducted jointly by the Maryland Department of Transportation, the Federal Railroad Administration and Amtrak.
About 85 Amtrak trains, 57 MARC commuter trains and two freight trains pass through the tunnel every day, and it is considered a major choke point for traffic along the Northeast Corridor.
The work this week was first announced by the MTA on Monday, when it warned MARC users to expect delays of up to 25 minutes during peak travel times and up to 10 minutes during midday periods as trains are forced to single-track through the tunnel.
The MTA said the work was being conducted between the West Baltimore MARC station and Penn Station, but didn't mention the tunnel by name. It said delays are expected through Wednesday.
Leeds said Amtrak crews are "working to inspect and return the track to service as quickly and safely as possible," but did not provide an estimate for when the work will be completed.
The state recently shortlisted three options for dealing with the deteriorating tunnel as part of its ongoing study: repair and restore the existing tunnel; build a new tunnel that sweeps north from the West Baltimore station before heading east toward a rail yard near Penn Station; or bring the rail line east from the West Baltimore station into the Midtown Edmondson neighborhood and then into a new tunnel that would cut a more direct line toward the rail yard near Penn Station.
The state also kept alive the option of doing nothing to the tunnel, though officials have said that option was kept mainly to serve as a baseline against which the other options could be compared.
In reality, the aged tunnel has far too many problems to do nothing, officials have said.
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