The sound of cable cars running up and down San Francisco's roller coaster hills hasn't been heard since March 2020, when a shelter-in-place order shut down the city at the start of the COVID-19 pandemic.The clickety-clack will be back the first week in August.San Francisco Mayor London Breed announced Tuesday that the cable cars will come out of hibernation in August for testing and operator training, running at a near-normal schedule, according to statement from the city.Riders will not be required to pay in August and will be invited to provide feedback on customer service and help operators get used to picking people up and dropping them off again."This is a 'mock service' trial, riding the lines where cable cars are operating and making stops," Eric Kato, a spokesperson for the San Francisco Municipal Transportation System, said in a statement. "This mock service will be irregular, not following a particular schedule."Regular service is slated to return beginning in September with the typical fares.Breed explained at a press conference Tuesday morning that Muni officials had said the cable cars wouldn't be ready for service until fall and she and Muni chief Jeffrey Tumlin came up with this creative solution in an effort to get people back on the cars before summer's end, according to CBS News. "What’s going to happen at the beginning of August is the cable cars will be available to all riders for the entire month of August for free of charge," Breed said, according to CBS. "So we are bringing them back a little earlier, not as early as I wished, but early enough so that you catch them at the end of the summer, right before you send your kid back to school when they open this fall, and they had better open this fall.”Masks will be required on cable cars as the state and county continue to require face coverings on public transit.