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.
Click here to follow Daily Voice Jersey City and receive free news updates.