Starting Friday, Pennsylvania Station in Manhattan will close the West End Concourse stairway, near Eighth Avenue and serving Tracks 20 and 21, from 5 a.m. to 3 p.m. daily.

The closures, needed for construction, will continue until next Thursday.

The work should not seriously impede Long Island Rail Road commuters because the West End Concourse is not as busy as the East End Concourse on the Seventh Avenue side of the station.

And the stairway will reopen just as passengers are rushing to catch afternoon trains — including the extra getaway trains the LIRR plans to add ahead of the Memorial Day weekend.