Even after paring back service twice this year because it could not muster enough engineers and equipment to fulfill its schedule, New Jersey Transit is still aggravating customers by canceling trains.

On the line that Mr. Leon rides, the railroad canceled the same train on three straight days.

Mr. Leon, 58, has been riding New Jersey Transit long enough to remember when it was a model of efficiency, held in high regard across the country.

An audit of the railroad that Mr. Murphy ordered just after his inauguration in January concluded that the fleet is so old that failing to replace any of its train cars in the next five years would pose “significant risk to the network and passengers.”

By next year, nearly 90 percent of those coaches will be at least 12 years old, absent any replacements, the audit showed.

Reports filed with the Federal Transit Administration show that the fleet has been shrinking and aging. The average age of its rail fleet was 18.6 years in 2017. By contrast, Metro-North Railroad, which serves the suburbs north of New York City, reported last year that the average age of its fleet was 15.7 years.

Four of New Jersey Transit’s locomotives were 37 years old, each having traveled more than 2.2 million miles, according to the 2017 data, and more than 150 of its passenger cars were at least 40 years old.

New Jersey Transit’s trains also break down more frequently than other commuter railroads. Data compiled by the Federal Transit Administration showed that New Jersey Transit’s trains had 236 major mechanical failures in 2017. That was far more than the 89 reported by Metro-North or the 132 reported by the Long Island Rail Road.