The 4:42 p.m. train from Penn Station to Babylon will be canceled, with customers being able to take the 5:03.
Passengers who take the 5:20 p.m train to Long Beach will be able to take the 5:23 train from Penn Station to Jamaica and then make all stops to Long Beach.
Passengers who normally take the 5:40 p.m. train from Penn Station to Seaford will be able to take the 5:47 train, which will make all stops between Rockville Centre and Seaford.
Scheduling changes in place to accommodate the shifting of all trains to two tracks will include the 5:36 p.m train from Penn Station to Babylon, which now will leave at 5:47 p.m. It will arrive in Babylon at 6:42, two minutes later than usual.
The 5:55 train from Penn Station to Long Beach will arrive at Long Beach one minute later at 6:52; while the 5:59 train from Penn to Babylon will arrive at 7:04 p.m., five minutes later than regularly scheduled.
The 6:44 p.m. train from Babylon to Patchogue will leave two minutes later than usual and arrive at Patchogue at 7:16 p.m. This is a result of a connecting train from Penn Station — the 5:37 — arriving at Babylon two minutes later.
The cancellations, which went into effect Monday, are expected to last for about one month.
MTA officials warned that the project will reduce the LIRR’s operational flexibility and greatly increase the impact on service should there be a major disruption. Extra rescue personnel and equipment will be deployed for the duration of the work.