Radnor and Haverford area commuters who ride the Norristown High Speed Line will need to swap trains for shuttle buses starting in Augusr, when SEPTA begins a 20-week service disruption that runs through December of this year.

The shutdown covers the second phase of a $55 million rehabilitation of the Bridgeport Viaduct, the 3,525-foot bridge that carries the M Line over the Schuylkill River between Bridgeport Station and Norristown Transit Center. Contractor J.D. Eckman is performing the work, which includes repainting the entire viaduct, replacing rivets, bolts and bearings, repairing the concrete substructure and replacing the concrete deck.

About 1,900 passengers cross the viaduct on a typical weekday, according to SEPTA's March 27 project announcement.

What changes and when

The disruption shifts in segments:

  • Saturday, August 1 through Friday, August 21: Shuttle buses replace trains between Norristown Transit Center and Bridgeport Station. Normal train service continues between Bridgeport and 69th Street Transit Center.
  • Saturday, August 15 through Sunday, August 23: Shuttle buses also replace Regional Rail Manayunk/Norristown Line trains between Norristown–Elm Street Station and Norristown Transit Center.
  • Friday, August 22 through Saturday, August 30: Shuttle buses replace M Line trains between Norristown Transit Center and Gulph Mills Station. Normal service continues between Gulph Mills and 69th Street. This segment directly affects riders who board at Gulph Mills, a key transfer point for bus routes 124 and 125 serving King of Prussia.
  • Monday, August 31 through Saturday, December 19: Shuttle buses again replace trains between Norristown Transit Center and Bridgeport Station. Normal service resumes south of Bridgeport to 69th Street.

For most of the 20 weeks, riders boarding at Radnor Station or Gulph Mills will have uninterrupted train service to 69th Street. The August 22–30 window is the exception, when Gulph Mills riders must use the shuttle.

"This 115-year-old viaduct is SEPTA's third-longest bridge, and this work is needed for us to be able to continue M service between Bridgeport and Norristown," Sauer said at the March event.

Planning your commute

SEPTA advises riders to plan ahead for bus-train connections and expect longer travel times. Real-time shuttle bus information will appear on separate pages on SEPTA's website, not on the standard M Line or Norristown Line schedule pages. Riders can map combined trips at plan.septa.org.

The shuttle schedule PDF for the Norristown Transit Center–Bridgeport segment is posted. The Gulph Mills shuttle schedule had not been posted as of July 20.

SEPTA customer service: 215-580-7800 (Mon–Fri 7 a.m.–7 p.m., Sat–Sun 8 a.m.–5 p.m.).

A third and final outage is planned for Sunday, January 18, 2027 through Saturday, February 6, 2027.