Transit workers in Philadelphia went on strike at 12:01 a.m. Tuesday, shutting down public transportation that provides nearly 900,000 rides per day.
A union representing nearly 4,700 workers went on strike after being unable to reach a contract agreement with the Southeastern Pennsylvania Transportation Authority.
The strike has raised fears that a long walkout could potentially keep voters from the polls on Election Day.
“We are hopeful that a tentative agreement will be reached before Election Day. If we foresee an agreement will not come to pass, SEPTA intends to seek to enjoin the strike for November 8th to ensure that the strike does not prevent any voters from getting to the polls and exercising their right to vote,” SEPTA officials wrote in a press release on their website.
"Despite months of constructive and innovative proposals from our side of the table, management has refused to budge on key issues including safety issues that would save lives and not cost SEPTA a dime," said TWU Local 234 President Willie Brown, who heads the union's negotiating team. "There is no new agreement, so we are on strike."
Brown also said that instead of heading to their shifts, union members will report to picket duty.
SEPTA said in a statement that negotiators are "ready and willing" to continue contract talks.
"The decision by TWU President Willie Brown leaves thousands of SEPTA customers without the transit services they rely on for travel to and from work, school and medical appointments," SEPTA said in a statement.
SEPTA posted a service interruption guide on their website since trains will be the only travel option in and around Philadelphia.
Union officials said the two sides are divided by pension and health care issues, also highlighting issues such as schedules, break time and driver fatigue.
Businesses, hospitals and schools have been preparing for a potential transit shutdown last week.
The Philadelphia school system will remain open, despite a potential impact. Nearly 60,000 public, private and charter school students use SEPTA for rides.
Democratic Gov. Tom Wolf urged both sides to continue talking until they can reach an agreement.
"Hundreds of thousands of Pennsylvania residents rely on SEPTA to travel each day to and from work and school and the inability of TWU and SEPTA to reach an agreement is devastating for many of these individuals and their families," Wolf said in a statement. "This will create extreme hardships for the city and for businesses."
Democratic Mayor Jim Kenney urged residents to "have patience during this period."
The Associated Press contributed to this report.