Contract negotiations resumed Wednesday between SEPTA and the union representing thousands of workers, more than three weeks after the union voted to authorize a strike.

Transport Workers Union Local 234, which represents 5,000 subway, trolley and bus operators and mechanics, has been working without a contract since Nov. 7. Sticking points in the current negotiations include better sick pay for workers and a two-year contract, instead of just one.

If a deal can't be met, John Samuelsen, international president of TWU, warned that a strike could "shut Philly down."

"We all authorize a strike," SEPTA body mechanic Lyle Smith said last month. "If it happens, it happens. Sorry for the public, but we gotta do what we gotta do for our families."

SEPTA leaders said they believe the ongoing conversations are a good sign. 

"We're not at the point of a strike yet. When talks are ongoing, when we have another session scheduled for Friday, we think that should provide a little bit of assurance," spokesperson Andrew Busch said. "Certainly, the union has already voted to authorize a strike, so they could call a strike if they feel that's necessary. Based on how the talks went today, we don't think that's happening immediately or imminently."

TWU has not set a strike deadline, and the two sides are set to talk again Friday. 

CBS News Philadelphia has reached out to TWU leaders for comment.

SEPTA negotiating with another union

SEPTA is also negotiating with SMART Local 1594, which represents more than 300 bus, train and trolley operators in Montgomery, Delaware and Chester counties. Members of that union authorized a strike on Nov. 21.

"They're asking me every day, 'What's going on? When are we walking?' I always gotta ensure them that I have to do things in good faith. And I will continue to talk to the company in good faith. But as of now, it's not looking too good," the union's general chairman Anthony Petty said Wednesday.

Petty said more negotiation is needed. 

"As of now, we're far apart," Petty said. "And I'm hoping there will be some relief soon because time is ticking." 

It's not clear when SEPTA and SMART Local 1594 will meet again.

Other SEPTA challenges

Funding and reliability challenges continue to loom large over SEPTA. Its trolley tunnel is scheduled to stay shut down through the end of the week for repairs, while Regional Rail lines continue to see delays because of federally mandated inspections and repairs on its Silverliner IV rail cars.

SEPTA was originally given until Friday, Dec. 5, to install thermal detection systems on the cars, but told CBS News Philadelphia Wednesday morning that the agency won't meet that deadline because of a supply shortage. 

"We expect 20-30 cars will still need to be completed," Busch said.

Busch said SEPTA won't be penalized by the Federal Railroad Administration.

Later this week, SEPTA will receive a delivery of rail cars loaned from Maryland Area Rail Commuter to help fill out trains while the work on SEPTA's rail cars is completed. A spokesperson told CBS News Philadelphia Amtrak is transporting the cars up to 30th Street Station from Maryland. The exact timing of the delivery is still being worked out.

Pennsylvania Gov. Josh Shapiro announced on Nov. 24 an injection of nearly $220 million in capital funds to SEPTA for safety and infrastructure improvements. Shapiro described the cash as a short-term fix after Pennsylvania's legislature passed a state budget without additional transit funding.

"I will keep fighting for additional recurring funding for mass transit in Harrisburg so that we can invest in mass transit systems, including SEPTA, all across the commonwealth," he said.