By Mark Abrams

PHILADELPHIA (CBS) — A crumbling Southwest Philadelphia bridge that carries thousands of vehicles a week and two SEPTA trolley lines is closing Sunday.

The Woodland Avenue Bridge between 47th and 48th Streets is being replaced under a program coordinated by PennDOT, the City of Philadelphia and SEPTA.

The bridge goes over tracks for SEPTA’s Media/Elwyn regional rail line.

The bridge itself carries SEPTA trolley routes 11 and 36.

“The bridge has been around since the 1920’s, so almost a hundred years of service – trolleys, vehicular traffic,” said SEPTA’S Heather Redfern. “The bridge is deteriorated. There’s speed restrictions on it, weight restrictions on it now. The bridge needs to be replaced in order to provide safe, reliable trolley service and also local vehicular flow.”

During the construction project, Redfern says the 11 and 36 trolleys will be detoured to Chester Avenue between 49th Street and the 40th Street portal. Vehicle traffic around the project will also be detoured.

The new bridge and other improvements are expected to be finished by summer 2019.