SEPTA will operate the city's subway and El lines overnight beginning in June pending final approval from its board in May.
The change is part of the transit authority's fiscal year 2014 capital budget plan, which goes through a series of public hearings over the next two weeks before the SEPTA board votes on it.
The overnight service would replace the the Market-Frankford NiteOwl Express bus lines, which run from midnight to 5 a.m., with train service during those same hours Saturday and Sunday.
SEPTA started researching and planning the relaunch of overnight subway service about six months ago, according to a SEPTA spokesman.
Several storms led the agency to operate overnight train service in place of the express buses this past winter, a safety decision to keep buses off icy roads.
The switch sparked a conversation among the public to reinstate the 24/7 subway service that was canceled in 1991.
"As a daily SEPTA rider, and a life-long SEPTA rider at that, I think this was long over due," said Conrad Benner, a popular blogger who garnered more than 2,500 signatures on a Change.org petition calling for the additional public transit option and coordinated an April Fool's hoax to draw more attention to his campaign.
The service will begin as a pilot program that will run from June until Labor Day and, depending on its success, SEPTA officials will decide whether or not to extend the overnight transit option through the fall.
Breaking news and the stories that matter to your neighborhood.
"I'm more than confident this so-called 'test period' will do well enough to continue offering this essential service well past Labor Day and indeed year-round," Benner said.
"I honestly think that once people have access to a service, it naturally becomes very difficult to take it away from them," he added. "I hope they can be extended to seven days a week before the end of this year to truly meet the needs of every Philadelphian."