PHILADELPHIA SEPTA may restore weekend late-night service on the Broad Street and Market-Frankford lines, agency officials said Thursday.

Because of increasing nightlife and residential activity in Center City, SEPTA may continue service after midnight, when subways now are replaced by "night owl" buses, general manager Joseph Casey said.

The service might continue until 3 a.m., officials said. Initially, it would be limited to Friday and Saturday nights, in a pilot program to test the response.

Chief financial officer Richard Burnfield said his staff was still assessing the costs - for security, operators, cashiers, and maintenance - to determine if a resumption of some late-night subway service would be included in the agency's proposed budget that will be released next month.

SEPTA halted late-night subway service in the early 1990s because of security and cost concerns. About 3,600 riders a day were forced to shift to nighttime buses.

Since then, SEPTA has been prodded to restore the service by some community leaders and by young people who want more after-midnight transportation.

"That's great news," said Conrad Benner, an advertising social media manager and blogger, who launched an online petition this week calling for late-night subway service.

Benner, 28, collected about 1,500 signatures in a little more than two days.

He noted that many late-night riders are restaurant workers returning home with cash, and they can feel unsafe waiting for a bus.

"I would rather be standing on a brightly lit El platform with cameras all around me and one SEPTA employee than on a street corner with a couple hundred dollars in my pocket," Benner said.

He predicted SEPTA's gingerly step toward more late-night service would generate "a lot of excitement."

"The city has changed," Casey said Thursday. "Now, with all the restaurants and people moving back to the city, it's time to reassess the situation."

Casey said SEPTA is not considering additional late-night runs on Regional Rail. In 2008, SEPTA added later runs on the Paoli, Trenton, and Manayunk/Norristown lines.

Additional late-night rail schedules likely would require more train crews, who already often work six days a week.