A top New Jersey Transit official tells state lawmakers the agency is considering possible disciplinary action after dozens of trains had to be canceled this week because of a manpower shortage.

NJ Transit Executive Director Steve Santoro said Wednesday at a joint Assembly-Senate hearing on track work at New York's Penn Station that there were 40 cancellations combined Sunday and Monday.

“We are doing everything within our control to maximize the number of employees filing the shifts to deliver the service we have scheduled,” Santoro said.

It's unclear whether all cancellations stemmed from engineers' labor contract rights that allow them to take two days to report for work when schedule changes are made. But Santoro told lawmakers that some employees had already scheduled vacation time before the commuter changes were put into effect.

Santoro says disciplinary action is governed by the labor contract.

“There is clearly an impact to our customers when our employees do not show up to work, and I think that message was made loud and clear,” Santoro said.

Santoro told lawmakers that the agency has 370 of 383 engineer slots filled and that this did not pose a problem until now. NJ Transit will meet with their engineers union Friday in the hopes of preventing further cancellations.

The Assembly Judiciary chair announced that he plans to subpoena NJ Transit. He wants the agency to provide all correspondence with Gov. Chris Christie about commuter changes, fares and revenues. Santoro said that he would comply.

The hearing came amid the second week of extensive repairs at Penn Station.

Lawmakers and an Amtrak official said the first week of work went better than expected.