She rode the shuttle for a couple of years until New Jersey Transit suspended the service last summer. Now she drives to the Princeton Junction station and pays to park there.

“It just became too much to rely on both trains to be on time and actually working,” she said.

Citing a lack of crew members or trains as a reason for failing to fulfill its schedule is not typical for commuter railroads. The other major commuter railroads in the New York City region, the Long Island Rail Road and Metro-North Railroad, rarely provide those explanations.

On Metro-North, the country’s second-busiest commuter railroad, just 73 of more than 95,000 trains — fewer than 0.1 percent — were canceled in the first five months of this year. And the Long Island Rail Road, the busiest commuter rail in the nation, had 356 cancellations through May .

Neither railroad keeps track of either “equipment availability” or crew shortages.

New Jersey Transit officials insist the problem is not an actual shortage of trains, just difficulties getting trains in place because of a lack of engineers.

They emphasize that cancellations have been less frequent this year than last and that the railroad’s performance appears to be improving. In the last few months, its trains have been running on time more often than last year, when performance sank.

Last year truly was an annus horribilis for New Jersey Transit.

On top of its crew shortage, it was saddled with a pressing deadline to equip all its locomotives with the technology for an automatic braking system known as Positive Train Control. The need to take those engines out of service for the installation forced the railroad to reduce its schedule, including the suspension of service on the Atlantic City Line and the Dinky.

At the end of the year, though, New Jersey Transit was sending out news releases announcing that it had completed that part of the installation. In May, it restored the suspended service.