Power play & L-train strain
NYC Transit President Andy Byford got sidelined from the L train slowdown at a contentious meeting Tuesday over the new approach to fixing the Canarsie tunnel.
The Metropolitan Transportation Authority shifted responsibility to its construction chief Janno Lieber and director, Veronique Hakim.
Byford — who had vowed to get an independent study into the L train repair proposal — was largely silent during the nearly four-hour, hastily-arranged MTA board hearing.
“Andy is responsible for, among other things, running the biggest rail system in North America,” acting MTA Chairman Fernando Ferrer said afterward. “On the L train, he’s responsible for service, communication with customers and all the other things, alternate service plans, that are involved in the L train renewal.”
In the meantime, the MTA board members who showed up to the last-minute meeting grilled engineers from WSP, the contractor that planned the original L train shutdown to repair the Canarsie tunnel, and is now validating the new approach.
The discussion raised questions about the effectiveness and safety of the new approach — issues that WSP officials said can be addressed.
The polymer that’ll encase the tunnel’s crumbling bench wall — used in bridges and the extension of the No. 7 line — is susceptible to fire, one expert said.
“If exposed to fire it will melt and it will give off fumes,” said WSP’s Michael Abrahams, an engineer with experience in bridges. The team is proposing a glass-fiber material to reduce that possibility. If necessary, a cement-like coating can make it fireproof. MTA engineers are confident in the safety of the material, which is used in the system, a spokesman said.
Meanwhile, the lifespan of the work depends on MTA keeping an eye out for cracks and maintaining it regularly — a responsibility that it couldn’t meet when it came to keeping track and signals in good working order.
“It certainly would have been advantageous for longterm service life to completely tear out the duct banks and completely replace them,” Abrahams said.
MTA officials had already dismissed the cable-racking suggestion years ago because of the damage it could do to the tunnel lining and cast-iron ring. They had also pitched a full shutdown because of the toxic silica dust that comes with demolishing concrete.
WSP officials explained how the plan changed, and why it was never pitched in the first place.
The racking system will use 60% fewer bolts, which will be 4 inches long going into a 10inch concrete tunnel lining, compared to the original evaluation.
To handle the silica dust, backers of the new approach say concrete demolition will be done on weekends only, giving crews time to clean up in time for the Monday rush hour. The experts suggested a thirdparty monitor to check on air quality, officials said.