TRAC questions MTA assertions about tunneling
The Transit Riders Action Council of Metropolitan Baltimore is disputing assertions from the Maryland Transit Administration about the hazards of tunneling under Little Italy, Fells Point and Canton to build the proposed east-west Red Line.
Henry Kay, the MTA's executive director of transit development and delivery, minimized the possibility of damage to historic buildings in those neighborhoods in an interview for an article published Tuesday in The Sun. He said the tunnel depth of the Red Line would be 40-50 feet deep, or comparable to the existing Baltimore Metro and that there should be no problems with noise or vibration on the surface.
Nate Payer, spokesman for TRAC, delivered the following response:
I feel compelled to make note that most of the existing Metro Subway tunnel is significantly deep than 40 to 50 ft, esp. in W. Baltimore area. Mondawmin Station is at least 60 to 70 feet down and Penn North Station is something like 90 feet under. Also of even more significant note: The Metro tunnel, at least west (or north) of State Center is bored through hard bedrock.
This is most certainly not the case for the proposed Red Line where most if not all of the greater downtown area tunnel would be on soft, unconsolidated earth of sand, silt, and clay. Tunneling through soft earth is more problematic and more difficult due to the inherent instability the material surrounding the tunnel bore. This is all well documented. In my research, I've yet to find a similar project in the US where a soft earth tunnel was bored so close to the surface with historic row houses or like above it as in the case where the tunnel is planned to pass under in Little Italy and a few shorter segments in Fells Point and Canton. (Maybe the MTA knows one.)
It should be pointed out that TRAC opposes the Red Line for reasons that have nothing to do with tunneling and everything to do with the group's preference for a heavy rail subway along a different route. Nevertheless, Payer's points deserve a response from the MTA. Clearly there is a difference between 40-50 feet down and 60-90 feet down.
We've asked for an MTA response and hope to pass it along soon.