SEPTA said it will pull a third of its Regional Rail cars out of service after discovering a “significant structural defect,” according to a statement released by the agency.

All 120 Silverliner V cars will now be out-of-service for inspections, the agency announced Saturday. The nature of the defect was not immediately identified by the agency.

Weekend and holiday schedules can be maintained with the remaining fleet of trains, so travel during the July 4th weekend will be unaffected, CBS Philly reported. However, transit officials are still working to develop contingency service plans for weekday travel, which would resume Tuesday.  

The agency said its General Manager, Jeff Knueppel, will speak at a press conference scheduled for 2 p.m. Sunday at SEPTA's Market Street headquarters in Center City to offer more details.