HOBOKEN, N.J. (CBSNewYork)NJ TRANSIT and its riders are facing a new problem – one that has nothing to do with the “Summer of Hell” track work.

Monday and Tuesday morning, some trains were not just delayed, they were cancelled altogether, because the agency didn’t have the engineers to drive them, CBS2’s Meg Baker reported.

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Tweets from NJ TRANSIT read, “cancelled due to manpower shortage” and “cancelled due to crew shortage.”

NJ TRANSIT said some of its employees are using a contractual loophole to take two days off from work.

A spokesperson said the clause dates back eons, giving workers the right to take 48 hours to choose a new assignment before a schedule change.

It works like a game of dominoes, with the most senior employees choosing first and down the line the assignments get changed, Baker reported.

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But NJ TRANSIT said due to summer vacations and this loophole, there are no extra engineers available to fill in, leaving customers in the lurch.

“It’s all our tax dollars that are being used in these facilities. I would say they should plan on doing something in which they have more of a workforce or somebody as a backup, so that our schedules are not effected,” commuter Varun Sheoran said.

“We have an emergency going on right now, Amtrak doing work, and the last thing you need to do is add more inconvenience to passengers by cancelling a train because you don’t want to work that particular shift,” President of the New Jersey Association of Railroad Passengers Len Resto said, calling it poor planning. “I would imagine that the clause was put in there to avoid situations of fatigue where an engineer may be asked to work a double shift, which they can’t do through FRA regulations. But it seems to me, there needs to be some common sense tied to that.”

A source with knowledge of NJ TRANSIT’s situation told Baker the real problem is chronic under-staffing by the Christie administration. He said engineers have not been hired in years, and if they do so now, it takes three years to train each one.

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If that’s true, larger problems are looming ahead, Baker reported.