The Long Island Rail Road’s Ronkonkoma branch is operating on or close to schedule after a signal problem near Central Islip temporarily disrupted service between Brentwood and Ronkonkoma, the LIRR said Tuesday.

About 5:30 p.m., the LIRR announced the resumption of service, which was suspended about 5 p.m.

Before service resumed, customers were advised to use alternate LIRR branches such as Port Jefferson, Babylon and Montauk, the railroad said earlier in a statement on its website. Limited bus service was also available.

LIRR spokesman Salvatore Arena said the railroad discovered the problem, a “bad insulated joint,” about 2 p.m. The issue necessitated taking a track out of service, which “immediately started affecting both eastbound trains and westbound trains that were scheduled.”

Repairs have been completed, the LIRR said.

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The LIRR reported three rush-hour delays related to the problem: The 3:55 p.m. train from Penn Station due at Ronkonkoma at 5:16 p.m. was delayed at Brentwood; the 4:22 p.m. train from Brentwood due at Penn Station at 5:38 p.m. was operating 10 minutes late; and the 4:48 p.m. train from Ronkonkoma due at Penn at 6:08 p.m. was delayed at Brentwood.

On board the 5:22 p.m. train out of Penn Station to Ronkonkoma, Mackenzie Mills, 29, of Medford, said she planned to have her boyfriend pick her up at Brentwood because she expected there wouldn’t be enough space on the buses.

“There needs to be better plans in place for disruptions like this. Many commuters park in the Ronkonkoma lots, so taking an alternate branch still leaves everyone stranded and in a jam,” Mills said in a private Twitter message. “It’s astounding that monthly commuters are already paying $377, don’t have reliable service, consistently have fares raised and service just gets worse.”