"If a work stoppage becomes necessary, it will involve all three TWU bargaining units" the statement said.
MAP: What will and won't be running in the event of a SEPTA work stoppage
SEPTA spokeswoman Jerri Williams said the union skipped a scheduled 9:00 a.m. negotiating session Friday morning and told SEPTA negotiators they would not return to the bargaining table on Friday.
LINK: SEPTA's online guide in the event of a work stoppage
Williams said "we remain hopeful" that an agreement will be reached without a work stoppage. SEPTA said it has asked the union for a 3-month contract extension but has received no response.
A short time later, a union source told Action News' David Henry that despite the skipped bargaining session Friday morning, a transit strike is very unlikely this weekend, and would remain unlikely until contracts with two other unions representing SEPTA workers expire on April 6th.
The source cautioned against reading anything into union negotiators' absence from Friday morning's session, Henry reported. The source said union negotiators were simply not prepared for the 9:00 a.m. session after bargaining late into the night Thursday night.
Issues figuring prominently in the current talks include worker pension funds and health care benefits in light of the Affordable Care Act going into effect this year.
Meantime SEPTA unveiled its alternate service plans Friday morning in case a strike does happen.
If there is a strike, Williams said, Regional Rail, CCT and suburban transit will continue to run.
Suburban buses running into Philadelphia will run on alternative schedules.
However, city transit lines including buses, trolleys and subways would not operate.
Fares and tickets would be collected on the concourse level of the regional rail stations, as they have been in past strikes.
Ambassadors and operations staff would be on hand to answer questions, Williams said.
Most TransPasses and weekly passes would be valid.
SEPTA currently serves about 825,000 riders per day. A 2009 strike by transit workers lasted six days.
The Associated Press contributed to this report.