The Long Island Rail Road said it is operating on or close to schedule systemwide Monday, after a signal problem outside of the East River tunnels that led to delays and cancellations on Sunday.

"We anticipate operating a regular a.m. rush today," the railroad said in an email alert sent out early Monday.

The Metropolitan Transportation Authority said the signal problem affected trains into and out of Penn Station, with commuters facing 45-minute delays, crowded trains and even cancellations -- all as workers attempted to fix the signal problem, railroad spokesman Salvatore Arena said.

As of 11 p.m. workers were still trying to fix the signal problem with work expected to continue overnight, Arena said.

The disruption was due to a signal problem at Harold Interlocking, a stretch of the railroad where multiple tracks converge and trains switch tracks between the Penn Station and Jamaica stops in Sunnyside, Queens, Arena said.

With Deon J. Hampton and Laura Figueroa

NewsdayTV's Doug Geed shows us some great spots 'Out East' to visit this summer. Credit: Brian Jingeleski, Randee Daddona

Out East Show: LI Aquarium, Patty's Berries and Bunches, Palmer Vineyards NewsdayTV's Doug Geed shows us some great spots 'Out East' to visit this summer.

NewsdayTV's Doug Geed shows us some great spots 'Out East' to visit this summer. Credit: Brian Jingeleski, Randee Daddona

Out East Show: LI Aquarium, Patty's Berries and Bunches, Palmer Vineyards NewsdayTV's Doug Geed shows us some great spots 'Out East' to visit this summer.

SUBSCRIBE

Unlimited Digital AccessOnly 25¢for 6 months

ACT NOWSALE ENDS SOON | CANCEL ANYTIME