SEPTA says it has reached a tentative agreement on a new contract with the Fraternal Order of Transit Police.
The terms of the agreement have not been made public. But transit police will head back to work beginning with the midnight shift.
Both sides still need to sign off on the new deal.
About 200 transit police officers have been on strike since March 21 over a wage increase. They have been working without a contract for about a year.
In their absence, city police, transit police supervisors and private security companies were deployed to patrol the system's subways, trains, buses and trolleys.