SEPTA passengers could be in for a rough ride once the Fourth of July holiday is over.

A day after announcing a third of its regional rail fleet had to be taken out of service due to a “significant structural defect,” the transit agency revealed more details on the problem and how it would deal with the reduced trains during the fix.

“Unfortunately it will be rough on our customers,” SEPTA General Manager Jeff Knueppel said during a Sunday afternoon press conference.

After 120 Silverliner V Regional Rail cars were pulled from service, it was revealed that cracks were found in most of their equalizer beams. The issue could have come from a design flaw or in the manufacturer process.

Knueppel described the situation as “all hands on deck” for SEPTA and asked for riders’ patience while the fixes are made.

Weekend and holiday service will not be impacted by the reduction in trains, but starting Tuesday SEPTA will be operating on a modified Saturday schedule, normally used for weather events, with additional trains to help ease rush hour commutes. There will also be boosted service on the Market-Frankford line, Broad Street line, Norristown High Speed line and Media-Sharon Hill line.

SEPTA warned of crowding at stations close to Center City and is also aiming to add parking near the Market-Frankford line, Broad Street line, Norristown High Speed line, according to 6ABC. The agency is additionally working with NJ Transit and Amtrak to see how they can help with the crowding.

Finally, for those who have purchased a weekly and monthly TransPass for July, SEPTA is developing a credit plan.

SEPTA said it is continuing to work on the overall transit plan and will have more details on its website Monday.

This defect in SEPTA’s regional rail comes just a few weeks before Philadelphia is set to hold the Democratic National Convention, with political participants from around the country ready to descend upon the city. When asked about how this transit setback may affect the DNC, Knueppel didn’t seem worried - saying the event would impact the Market-Frankford and Broad Street subways more.