The Long Island Rail Road said buses will replace trains early Saturday between Ronkonkoma and Farmingdale.
The railroad said it will be doing inspections and track work on that section between midnight and 8 a.m. as part of its double-track project.
Four trains in each direction will be affected and riders should plan for up to 50 minutes of additional travel time, the railroad said.
The four Ronkonkoma Branch trains that depart Penn Station at 12:14 a.m., 1:21 a.m., 2:53 a.m. and 4:43 a.m. will terminate at Farmingdale and connect to buses stopping at Pinelawn, Wyandanch, Deer Park, Brentwood, Central Islip and Ronkonkoma, the LIRR said.
Buses are scheduled to depart Farmingdale 10 minutes after the arrival of the trains from Penn Station.
The four trains that normally originate at Ronkonkoma will be replaced by local and express buses at 11:55 a.m., 11:57 a.m., 1:21 a.m., 1:23 a.m., 2:55 a.m., 2:57 a.m., 4:46 a.m. and 4:48 a.m., the railroad said.
Those buses will make stops at Central Islip, Brentwood, Deer Park, Wyandanch, Pinelawn and Farmingdale, the LIRR said.
The buses to Farmingdale will connect to westbound trains departing 10 minutes after their arrival, the railroad said.
The work is part of the $387 million double-track project that is expected to increase capacity along the 18 miles between Farmingdale and Ronkonkoma when it is completed at the end of next year.