The crack in SEPTA's rail cars has led Uber and the Philadelphia Parking Authority to heal their own breach.

The city regulatory authority and the ride-hailing app giant have reached a temporary agreement to allow Uber to operate legally in Philadelphia. This comes just a week after state legislators said a bill that would have regulated the hail-by-app industry was too unwieldy to vote on before the summer recess.

"It's taking away the stigma. We will make it legal here pending the legislation," said Vince Fenerty, the PPA's executive director.

That is good news for Philadelphia commuters, who need all the help they can get. A third of SEPTA's Regional Rail fleet is out of commission after inspectors found cracks in a key load-bearing component on 115 of SEPTA's newest cars. Taking those cars out of service has meant delayed and jam-packed trains and has left rail riders scrambling for another way to travel. Uber says its carpooling service, UberPool, will be a major draw while rail is hobbled. Use of the service increased 26 percent this week over last week. When the PPA offered a detente Tuesday, the company took it, the two parties said.

Uber is already offering a 40 percent discount to suburban riders who use its service to travel to and from certain SEPTA stops.

UberPool "is a benefit that other modes of transportation do not have," said Jon Feldman, Uber's general manager for Pennsylvania. "It can be a piece of the solution to help people move around."

While UberX has continued operating in Philadelphia despite its questionable legal status and the PPA's occasional enforcement efforts, the two parties said granting the service official recognition was important in the run-up to the Democratic National Convention, which arrives in less than three weeks, along with 50,000 visitors.

"I think that's very important for their business model and for the city," Fenerty said. "They had a cloud over it."

As Uber and the PPA made up, SEPTA tried to make do with its diminished fleet. Five trains filled to capacity bypassed platforms during the Wednesday morning commute, and riders continued to see delays nearing an hour and a half. SEPTA warned again that the difficulties might still get worse.

"The part we're still not sure about is how many people may even be coming back [from vacation] next week that we didn't see yesterday, didn't see today," said Andrew Busch, a SEPTA spokesman.

Trains were slowed even further Wednesday by the heat, which can cause lines to sag. That heat-related speed restriction is expected to last throughout the week.

SEPTA is coping by running fewer trains with more cars attached. It also wants to borrow cars from neighboring rail agencies, and Amtrak is adding stops in Ardmore to make up for drops in SEPTA's service. NJ Transit could also take over some operations between Trenton and 30th Street Street Station.

Sharon Williams, dispatch manager at Philadelphia Taxicab Service, said Wednesday that the service was "swamped all day," although she said that might have been due to the heat. She said business started to become busy Tuesday afternoon and picked up again around 11 a.m. Wednesday. Busch said there had been an uptick in ridership on the Market-Frankford Line, but not on the Broad Street Line.

One of those who switched to city transit was Kevin Dunleavy, 54, of Lower Merion, who abandoned his usual route along the Paoli/Thorndale line from Overbrook to Suburban Station for a combination of the Market-Frankfort Line and the Route 65 bus.

"I've heard stories of two-, three-hour commutes," he said. "I'm happy to have avoided it."

The PPA will take no action against Uber drivers through Sept. 30, and the hope is that legislation will establish a statewide regulatory framework for the ride-hailing industry by then.

The agreement does not address many of the issues that held up the legislation. The PPA will collect no tax revenue or have any regulatory authority, its authorities said, though sources with knowledge of the agreement said Uber would pay the PPA several hundred thousand dollars for outstanding fines. It is simply standing aside.

Lyft, a competing app service, was offered the chance to be involved but has not responded, PPA officials said.

Lyft tells a different story, saying it had not refused to talk with the PPA.

"Lyft has worked and continues to work with the PPA," spokeswoman Chelsea Wilson said.

The cause of the grief for SEPTA trains is an equalizer beam that transfers the weight of the 146,000-pound train car to its axles. Fatigue cracks in the area of a welded piece have made the vehicles, some of which have been in service only three years, unusable. How long the pain will last for SEPTA riders depends on whether the cracks can be temporarily welded until replacement beams arrive, or whether the authority must wait for new parts. Hyundai Rotem, which supplied the cars, is likely to play a big role in repairing the flaws, but almost a week has passed since the problems surfaced, and what that role will be is unclear.

The company is responsible for repairs needed in the event of a "defect in design, material or workmanship," according to the 2006 contract that ordered the now out-of-service Silverliner V rail cars, and is responsible for the costs of labor. SEPTA has communicated with the company and has said its personnel are coming to Philadelphia to work on the cars.

"The team that has been assembled of all the different parties involved is a well-educated, well-experienced group," said Andrew Hyer, a Hyundai Rotem spokesman.

The contract also states that all material used for construction must be new and of the best quality. Another open question is whether the cracks formed because of the materials used, the design of the cars, or something related to the assembly of the cars. Ace Precision in Akron, Ohio, which made the beams, declined to comment Wednesday. Hyundai Rotem has not responded to questions about what might have caused the problems or how it might resolve them.

Staff writers Joseph N. DiStefano, Olivia Exstrum, and Daniel Block contributed to this article.