A new timetable went into effect Tuesday on the Long Island Rail Road to reflect the impact of several work projects.

Track work on the Port Washington branch will result in midday trains departing up to seven minutes earlier, the railroad said.

There also will be track work that requires “slight adjustments” to weekday, off-peak departure and arrival times on the Long Beach and Ronkonkoma branches, the railroad said.

On weekends, there will be changes on the Huntington/Port Jefferson, Ronkonkoma and Montauk branches, the LIRR said.

Beginning on Sept. 17, the LIRR said it will be replacing switches that will affect trains on the Ronkonkoma branch because one of two Main Line tracks will be out of service between Hicksville and Farmingdale for about 48 hours.

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In addition, construction on the LIRR’s Main Line Double Track Project will be performed on Sept. 24 and 25. These two projects will impact the Ronkonkoma and Montauk branches.

Passengers can get more information by picking up a copy of the timetable at LIRR stations or at mta.info on the web.