The Philadelphia transit system's largest union went on strike early Tuesday, stalling the city's bus, subway and trolley operations a day after the World Series shifted to New York and forcing commuters to scramble to find other ways to get to their destinations.

The strike by Transport Workers Union Local 234 will all but cripple a transit system that averages more than 928,000 trips each weekday. The union represents more than 5,000 drivers, operators and mechanics of the Southeastern Pennsylvania Transportation Authority.

"There will be people waking up this morning needing to commute into work. And unfortunately, there's not going to be service for them," said SEPTA spokeswoman Jerri Williams.

The union had threatened to go on strike during the World Series. But over the weekend Gov. Ed Rendell ordered the union and SEPTA to remain at the bargaining table or risk consequences.

Willie Brown, the local's president, said they decided to strike after both sides agreed that they had gone as far as they could in negotiations. The announcement came just hours after the Phillies beat the Yankees in Game 5 of the World Series, the last game to be played at Citizens Bank Park. Brown said the strike was effective as of 3 a.m. Tuesday.

The doors to subway stations were gated off Tuesday and no buses crawled the streets in the city's downtown corridor. Commuters trying to get to work said they had to make last-minute accommodations when they awoke to word of a strike.