The Long Island Rail Road said it anticipates a normal Thursday evening commute after delays of 10 to 15 minutes on about half of its peak trains during the morning rush.
Those delays were "due largely to a Penn Station signal problem" at about 6:45 a.m. "that limited the use of one of the East River Tunnels connecting Queens and Manhattan," LIRR spokesman Salvatore Arena said in a statement.
Arena said that "track damage discovered two hours earlier on the Main Line between Mineola and Carle Place" contributed to the delays.
The spokesman, citing MTA police, said "vandals had stripped copper wiring from the tracks in two locations, resulting in a small fire that caused some track damage."
While the damage was repaired, trains traveled at reduced speeds through the area, he said. The vandalism is under investigation.
"MTA police have made arrests in the past for the theft of copper along the LIRR right-of-way, a risky crime given the high-voltage dangers, and the LIRR has stepped up efforts to secure such equipment," Arena said.
The railroad stressed that fail-safe systems ensured against any safety issues.
The disruptions affected service to Huntington, Port Jefferson and Ronkonkoma.
Additionally, the signal trouble at Penn Station affected service to Manhattan and forced trains on the Babylon and Hempstead branches to terminate service at the Atlantic Terminal. Riders were able to access the subway.