The wicked January weather that left moon-crater potholes in highways and buried cars in driveways also stopped train riders in their tracks.

It was NJ Transit’s worst month for train delays in six years.

Trains were late six or more minutes 8.8 percent of the time last month, the worst showing since January 2005, when the number was 11.1 percent. Last year, only 4.1 percent of trains were tardy for the same month.

A train is considered "on time" if it arrives within five minutes, 59 seconds after its scheduled arrival.

Last month, 1,588 trains were delayed six or more minutes. The key causes included severe weather conditions on Jan. 12 and 27 and a vehicle that blocked the North Jersey Coast Line tracks on the 14th.

Breaking down the statistics even more, NJ Transit trains on the busy Northeast Corridor Line between Trenton and New York City were late 24.9 percent of the time during peak commuting hours.

"The dates of the delayed trains just kept blending together and piling up," said John W. Nabial Sr., a commuter who uses the Northeast Corridor to travel from Princeton Junction to New York City.

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During one ice storm, Nabial didn’t get on his scheduled 5:37 a.m. train until 6:15 a.m. and didn’t arrive at New York Penn Station until after 9 a.m. The trip usually takes a little over an hour.

A broken-down train and signal outage — announced on Nabial’s train just after it pulled out of Newark Penn Station — added to the hellish commute.

NJ Transit spokesman Dan Stessel said on-time performance always dips in the winter — sometimes in December, sometimes in January, and both months this season.

In December 2010 and December 2009, for example, trains were late 7.8 percent of the time. NJ Transit’s goal is 5 percent or lower.

"January’s on-time performance is what you’d expect in a month of extreme weather," Stessel said. "We played the hand we were dealt as best as we could. We believe the system performed better in January than similar extreme-weather months in past years."

He provided some historical perspective to illustrate how reliability used to be much worse during winter.

In February 1994, 21 percent of trains were late, following a month in which 20.1 percent of trains were late. In January 1996, 15.2 percent of trains were late.

Tom Calabria, who commutes from West Windsor to New York, said NJ Transit could do a better job of giving information to train riders during delays, but he understands the transit agency faced significant weather challenges.

"It was a horrible month," he said. "Lots of equipment out of place, canceled trains, combined trains — all of which compounded crowding in some instances."

NJ Transit’s three light rail lines — Hudson-Bergen, River Line and Newark — fared better in January, with 5.6 percent of those trains being tardy.

Previous coverage:

• N.J. weather conditions improve as snow, freezing rain turn to rain

• Blizzard update: PATH service fully restored at all stations, delays on New Jersey Turnpike

• Train service is restored between Newark, New York with some delays

• NJ Transit expects normal evening rush following extensive morning delays due to damaged wires

• NJ Transit trains resume schedule following power problem

• NJ Transit trains once again facing delays