3:40 p.m. update: The union representing MARTA employees says it does not support a sick-out that has disrupted bus service for the last two days.

"It's not a sick-out by us," Britt Dunams, vice president for maintenance for the Amalgamated Transit Union Local 732, told The Atlanta Journal-Constitution Tuesday afternoon. "ATU has not sanctioned or approved any sick-outs."

The union reached a tentative labor agreement with MARTA on Saturday. Dunams said the ATU plans to put the proposed MARTA contract to a vote in the next few days. He declined to speculate on whether it would pass.

“That’s an interesting question,” he said. “It’s like any other electoral democratic process.”

“We just want the riding public to know that we’re supporting service being in place for them,” Dunams added.

Original post: "We just want the riding public to know that we're supporting service being in place for them," he said.

Labor unrest at MARTA has disrupted bus service for a second day.

The agency posted dozens of notices for delays on numerous bus routes on social media early Tuesday. It followed a pattern set Monday, when about 80 bus drivers called in sick.

“There are sick calls coming in, and there are delays because of it,” MARTA spokeswoman Stephany Fisher said Tuesday morning. “We’re working to inform customers what routes are impacted.”

Fisher said 73 operators had called in sick as of mid-morning Tuesday – many of them the same drivers who called in the day before. MARTA has 1,199 full-time bus operators and 49 part-timers.

MARTA plans to seek a court injunction forcing the Amalgamated Transit Union Local 732 to disavow the sick-out and get employees back to work. Fulton County Superior Court is closed Tuesday because of inclement weather. But Fisher said the petition would be filed as soon as the court opens Wednesday.

MARTA and its union have been negotiating a new contract, and the agency says the parties signed a tentative agreement Saturday.

However, that apparently has not satisfied some employees. The union has not responded to requests for comment.

As on Monday, Tuesday's disruption does not appear to have affected MARTA rail service – a crucial transportation link for visitors in town for Super Bowl 53. However, the disruption to bus service may inconvenience tens of thousands of local residents who catch buses to work and elsewhere each day.