The Long Island Rail Road said it will be doing work on the Port Jefferson Branch on Sunday, causing schedule changes.

Buses will substitute for trains between 7:30 a.m. and 7:30 p.m. at the St. James, Stony Brook and Port Jefferson stations, the railroad said.

Crews will be working on the Stony Brook Road Bridge during those hours, but Stony Brook Road will remain open, the railroad said.

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Eastbound riders to St. James, Stony Brook and Port Jefferson will get off at Smithtown and board buses for the rest of their trip, the LIRR said. Customers should allow for up to 25 minutes extra travel time.

Westbound, buses will leave up to 30 minutes earlier than scheduled train times from Port Jefferson, making stops at Stony Brook and St. James stations, in an effort to maintain normal train service from the Smithtown station, the LIRR said.