The closure will "allow crews to complete a track and timber replacement project and perform minor structural repairs. The Viaduct will be closed through November 2013," SEPTA said.
Substitute shuttle buses will be put into service to continue serving passengers on the northern end of the 13.4-mile line, an interurban route linking Norristown, Pa., with Upper Darby, Pa., using third rail power.
"The bridge was built in 1911 and is showing signs of deterioration like cracks, spalling concrete and corrosion," said SEPTA Deputy General Manager Jeff Knueppel. "More important, the bridge ties that sit directly upon the steel structure and hold the rail in place are rotting and failing."
SEPTA asserts that "a significant loss of capital funding over the last three years" has forced it to defer rehabilitation work, though design work was completed by 2011.
Temporary repairs, speed restrictions, and increased inspections have occurred since 2011, but "we have exhausted all possible temporary timber repair measures," said Knueppel. "Without full timber replacement, we would have no choice but to permanently close the bridge."
Railworks Track Systems of Sewell, N.J., will oversee the $7.5 million project, scheduled for completion in November.
On weekdays during construction, trains will operate between 69th Street Transportation Center and Bridgeport Station. Shuttle buses will be used to transport customers across the Viaduct between Norristown Transportation Center and Bridgeport Station, SEPTA said.