LIRR Main Line

LIRR Main Line

The Main Line is a rail line owned and operated by the Long Island Rail Road in the U.S. state of New York. It begins in Long Island City and runs along the middle of Long Island about 95 miles (153 km) to Greenport. A mile east of Long Island City (east of Hunterspoint Avenue) the four tracks of the East River Tunnels join the two tracks from Long Island City; most Main Line trains use those tunnels rather than running to or from Long Island City.

Continuing east, five branches split from the Main Line; in order from west to east, they are:

• Port Washington Branch (at Wood Interlocking in Woodside, Queens)
• Hempstead Branch (at Queens Interlocking along the Queens / Nassau County border)
• Oyster Bay Branch (at Nassau Interlocking, east of Mineola station)
• Port Jefferson Branch (at Divide Interlocking, east of Hicksville station)
• Central Branch (at Beth Interlocking, east of Bethpage station) – a single non-electrified track with no stations, connecting the Main Line to the Montauk Branch

Public timetables refer to the Main Line east of Hicksville as the Ronkonkoma Branch.

Trains on the Main Line between Long Island City and Ronkonkoma are governed by Automatic Block and Interlocking Signals and by Automatic Train Control (known as Automatic Speed Control by the LIRR). East of Ronkonkoma to Greenport trains operate in non-signalled or "Dark Territory", with all train movements governed by train orders and timetable authority.