Labor talks resumed Sunday between SEPTA and Transportation Workers United Local 234 in an effort to reach agreement on a new contract before Monday's midnight strike deadline.

A strike by bus, trolley and subway operators could come as early as Tuesday and - if unresolved for a week - could affect voters' ability to get to the polls Nov. 8.

Suburban buses and trolleys would continue to run and Regional Rail would not be affected.

SEPTA's management laid out in detail Friday its existing contract with almost 5,000 workers threatening to strike, illustrating why it thinks a strike is unnecessary.

Union members pay $46 a month for medical care that Board Chairman Pasquale Deon described as a Cadillac plan. They can retire at any age after 30 years of service and get their full pension, cannot be laid off, and, with overtime, average $68,100 a year.

"I think we give these guys a really fair deal," Deon said in a conference call with members of the Inquirer Editorial Board.

Local 234 members disagree. With just three days before their contract expires, the union's 4,738 members are ready to strike if SEPTA does not address pension disparities, the possibility of a big bump in health-care costs. and work conditions the union says put the public in danger.

"I'm not agreeing to anything that treats my people as second-class citizens," said Willie Brown, president of the local.

Brown described minimal progress at the negotiating table. Even policy changes that would not cost SEPTA more have been difficult to resolve.

"It's very slow," he said. "The simplest things become big issues. It's almost like it's not negotiations."

A strike will begin if the parties don't reach an agreement by 12:01 a.m. Tuesday, and all three modes of transit will come to a standstill in the city.The last strike, in 2009, lasted six days. A strike in 1998 lasted 40 days.

The pension, both sides say, is one of the biggest sticking points in negotiations underway at the Sheraton hotel at 17th and Arch Streets. Workers' pensions are capped at $50,000. If they make more than that, they keep paying into the system but do not reap the benefits when they retire. This contrasts with those in management, union representatives have said, who don't have capped pensions.

The cap for workers is nothing new, SEPTA management said. It's been in place since 2005. And management's uncapped pensions are a valuable incentive to attract hourly workers to management jobs, said Rich Burnfield, SEPTA's deputy general manager. About half of the authority's managers are culled from the ranks of its workers, he said.

Union representatives rejected that argument, saying hourly workers who move to a management job receive a considerable pay bump. They say they simply want fairness, and that they have argued for a pension that would allow workers to benefit from the money they pay into the system without costing taxpayers more. Until recently, workers were also contributing a larger percentage of their pay for pensions than managers.

Unions have framed the current pension system as one in which money paid in by workers subsidizes managers' pensions, but Burnfield said the contributions from the two groups of employees are tallied separately.

SEPTA has a $1.2 billion pension obligation that is about 62 percent funded. SEPTA is paying about $98 million into the system this fiscal year.

On health care, SEPTA managers say they are considering adjusting a plan that currently requires workers to pay about $552 a year for health care, not including co-pays for appointments and prescriptions. Medical, prescription, dental, vision and life insurance cost SEPTA $227 million in fiscal 2017, a significant portion of its $1.4 billion operating budget.

SEPTA is proposing that workers can still pay their current contribution, but in return would get minimal coverage. To get a plan that matches their current benefits, union members argued, would cost them 11 times as much as they now pay, raising their annual contribution to about $6,000 a year.

The union is also fighting for greater quality of life for workers. Matters like bathroom breaks and down time between shifts may seem trivial, representatives said, but they are critically important to vehicle operators who have no flexibility while on the job and who can endanger lives if they are working while tired. SEPTA counters by saying it is already taking steps to adjust shifts, and questioned why these issues were being raised publicly now.

"You don't wait until a union contract to talk about safety," Burnfield said.

The 2009 TWU strike coincided with an election day, but this year the strike could overlap with a presidential election in which Philadelphia and its surrounding counties are poised to be a decisive battleground. The city commissioners, who oversee elections, have said voters should be able to walk to polls and a strike should not affect turnout, but the possibility of a strike dragging out to election day has raised concerns. Gov. Wolf is in contact with both union representatives and SEPTA, spokesman Jeff Sheridan said, and is urging a compromise.