Arlington Transit bus operators participating in the strike that has caused delays on ART routes Monday and Tuesday have been suspended pending investigation. The union disputes that and says drivers are being fired.

“Those who did not return to work yesterday have been placed on suspension pending investigation,” said William P. Forsythe, chief executive of Forsythe Transportation, which contracts with Arlington County to run the ART system. Drivers can be fired after the investigation, he said.

“They didn’t do the investigation. They just went to suspension,” said Charles Smith, a union representative for American Federation of State, County and Municipal Employees Local 3001. “Now they are investigating after the fact.”

There are 23 union members out of ART’s 80 drivers. A few of those drivers returned to work, but Forsythe could not give a definitive number. He said the remainder were sent letters notifying them of the company’s action.

“This is an illegal, wildcat strike” that violates a term in the drivers’ contract with Forsythe, which expires in October, he said.

The union has tried to discuss their complaints with Forsythe using a mediation service multiple times, Smith said. Their complaints include unfair labor practices, including not allowing drivers to leave their buses to use the restroom and sexual harassment by managers.

The union should be a partner in the company, Smith said. They want to “improve working conditions so that [drivers will] find it advantageous to stay,” he said.

Forsythe denied the charges and said the company tried to sit down with the union to discuss their grievances this week, but was denied.

Some 29 of 32 bus runs Tuesday morning were completed, or 90 percent, Forsythe said. Only 60 percent of Monday’s bus runs were completed.

“Today, they are more on time than they were yesterday,” Forsythe said. “We are very confident we’ll be able to restore service fully and very quickly,” he said.

Supervisors, dispatchers and other certified personnel are filling in for the striking drivers. Training for new bus drivers is being held throughout the week, Forsythe said.

Arlington County alerts state ART service delays will continue through the evening.