Service was suspended in both directions between Chatham and Mount Tabor due to an issue near Mount Tabor, NJ Transit said.
M&E and Gladstone Line trains were being diverted into Hoboken.
The issue caused a disruption to hundreds of commuters, according to some who took to X for guidance.
"Hundreds of people standing at maplewood station," one said in a Tweet. "No announcements for over 25 mins. Where are the trains? Are 6314 and 312 running?"
NJ Transit provided updates promptly.
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