The Maryland Transit Administration is considering changing the front-running proposal for the Red Line to require east- and westbound light rail trains to share one track through a mile-long tunnel - a plan that might save $60 million or more but could pose operating difficulties and raise safety concerns.
Building a single-track tunnel under Cooks Lane - a narrow street at the city-county line that connects Edmondson Avenue with Security Boulevard - is intended to reduce the Red Line's cost and bring it within federal funding guidelines. Without such cost cuts, the entire project from Woodlawn to Bayview could collapse.
"Single-tracking" is a phrase that leaves a sour taste in the mouths of Baltimore-area transit riders. Much of the existing Central Light Rail Line was originally built as a single-tracked line, but trip delays and other service problems forced an eventual retrofitting project that involved extended service shutdowns.
MTA Deputy Administrator Henry Kay confirmed that the single-track option is under consideration. "We're looking at a whole variety of things we can do to bring the cost-effectiveness into alignment."
The Federal Transit Administration imposes a rigid formula of cost-effectiveness for funding of construction of local transit projects. Projects above a certain threshold - $24.49 in the arcane cost-benefit formula employed by federal bureaucrats - will not be considered.
The plan preferred by the city administration, known as Alternative 4C, has been estimated to cost $31 under that formula. The MTA has said it can find ways to sweat enough costs out of the plan to meet the federal guidelines.
Under 4C, the MTA would build a light rail line that would operate in one tunnel under downtown, Harbor East and Fells Point and another under Cooks Lane. The trains would operate on the surface along Edmondson Avenue in West Baltimore and Boston Street in Canton - a provision that has aroused bitter opposition in those neighborhoods.
The MTA has determined that a proposal that would include tunneling in Canton and in West Baltimore would be far too expensive for federal guidelines.
Instead, the agency is looking for ways to reduce the tunneling in Alternative 4C. The modification it is considering would excavate only one tube under Cooks Lane, while leaving room to add a second bore in a future double-tracking project.
While the single-tracking proposal could shave $60 million to $70 million off the cost of the project, it creates an inviting target for critics of the Red Line 4C plan.
"This is a sign of how little likelihood they had without doing this of meeting the cost-effectiveness criteria," said Ed Cohen, past president of the Transit Riders Action Council and an advocate of building a subway rather than a light rail line.
After the existing Central Light Rail Line was opened in the early 1990s as a largely single-tracked line, the system was fraught with problems that made service unpredictable. Single-tracking came to symbolize the widely held view that the line was "done on the cheap."
Years later, the light rail was retrofitted with double-tracks in all but a few places at a cost of $154 million. But that project forced yearlong shutdowns of the northern and southern stretches of the line from 2004 through 2006.
While MTA officials and consulting engineers say they would prefer a double-tracked Red Line, they say single-track operations under Cooks Lane would be feasible because it is near the western end of the line instead of near the middle.
"You want to have the Cadillac, but sometimes you can't afford to have the Cadillac," said Kay. "It's not that single-tracking is never done or never works."
Tom Hannan, a project engineer with the firm of Whitman Requardt & Associates LLP, said single-tracking wasn't the first choice in the planning of 4C. "We were trying to put together a system that was end-to-end double-tracked."
Hannan said surface light rail on Cooks Lane would pose a number of problems, including the narrowness of the right of way, the hilly terrain and the potential impact on the community.
Single-tracking would require a sophisticated signal system to ensure that trains going in opposite directions never occupy the tunnel at the same time.
"There are single-track operations all over the country working safely as we speak," Kay said.
The current light rail system uses a signaling system to keep trains apart at its single-tracked stretch near Hunt Valley, and even when it was largely single-tracked, the system never had a head-on collision of two trains.
Trains in the tunnel would be traveling at about 50 mph, Kay said, and he acknowledged that he couldn't guarantee that a signal malfunction would never happen.
Cohen said the results of any system failure could be catastrophic. "If there were a head-on train collision in the tunnel, the trains would have no survivability space."
Cohen's suggestion is that the MTA go back to the drawing board, restudy all options - including TRAC's proposals for a subway - and reapply for federal funding under the new rules he hopes will be in place after the next federal transportation reauthorization bill is passed.
But Kay said such a deal would likely push a project that is now expected to be complete about 2015 closer to 2020. The MTA official said the state would have the option of pushing forward with the Red Line with a single-track tunnel but adding a second bore later if the rules are changed.
Gov. Martin O'Malley is expected to make a decision by the end of summer on whether and how to proceed with the Red Line, Kay said.