Thousands of Philadelphia mass transit system workers could go on strike soon if an agreement is not reached through ongoing negotiations. Transport Workers Union Local 234 members voted last week to authorize a strike once their one-year contract with the Southeastern Pennsylvania Transportation Authority expires at 12:01 a.m. Friday. Union President Brian Pollitt said Thursday that he's willing to continue talks with SEPTA to avoid a work stoppage, but he warned that he may “have to pull the plug” if it doesn’t appear that progress is being made. SEPTA, which has repeatedly said its financial health is uncertain, said it remains hopeful a fair deal can be reached.