With a 3-month track maintenance project complete, regular midday service on the Long Island Rail Road's busy Ronkonkoma branch is set to resume Monday morning.

Since July 23, buses have replaced midmorning and early-afternoon trains between Farmingdale and Ronkonkoma, adding 18 to 32 minutes to commutes. The Metropolitan Transportation Authority was wrapping the final phase of its wooden-tie replacement work along the Ronkonkoma track.

advertisement | advertise on newsday

About 13,000 of the line's old oak track ties have been replaced since May 14, part of a project to ensure greater service reliability and less bumpy rides, MTA officials said. The ties have a life span of about 30 years and are replaced in cycles.

Weekday eastbound trains from Penn Station to Ronkonkoma that will return to uninterrupted runs are: 8:14 a.m., 9:14 a.m., 10:14 a.m., 11:14 a.m., 12:14 p.m. and 1:14 p.m. The weekday westbound trains with restored service are: 9:41 a.m., 10:41 a.m., 11:41 a.m., 12:41 p.m., 1:41 p.m. and 2:41 p.m.

Buses had been running east from Farmingdale to Ronkonkoma and west from Ronkonkoma to Hicksville.

The regular maintenance work comes as the MTA makes plans for a second track from Farmingdale to Ronkonkoma. A first phase is expected to cost $138 million, and the entire track could be laid by 2018, MTA leaders have said.