A computer glitch at New York's Grand Central Terminal forced all Metro-North commuter trains on all three lines to grind to a halt and stop in place Thursday evening, snarling late rush-hour traffic, officials said.
Metro-North is the second busiest commuter rail line in the country — after New York's other service, the Long Island Rail Road.
"Metro-North service remains suspended on all lines due to system-wide signal problems," a statement posted online read. "All trains are at a standstill until the railroad can troubleshoot the computers in its Operations Control Center to identify the problem."
Hundreds of commuters were forced to wait inside trains or at rail stations for hours as crews attempted to fix the problem. Officials said the trains have electricity and heat.
Metro-North riders at Grand Central and on trains along the three routes told NBC New York their trains were stopped at around 7:30 p.m., and that they were told crews were attempting to "reboot" the signal system.
Service was restored by 9:40 p.m., according to a tweet from the MTA.
"Metro-North train service has been restored on the Hudson, Harlem and New Haven," a statement read. "Customers should expect significant residual delays."