PHILADELPHIA (AP) — President Barack Obama on Saturday forced union workers in Philadelphia’s commuter rail strike to return to the job, granting Pennsylvania Gov. Tom Corbett’s request to create a presidential emergency board to mediate the contract dispute.

Obama ordered the establishment of the three-member board effective at 12:01 a.m. Sunday. He called for “a swift and smooth resolution” of the dispute between the Southeast Pennsylvania Transportation Authority and its engineers and electricians unions.