High Quality Content by WIKIPEDIA articles! The South Side Railroad of Long Island was a railroad company in the U.S. state of New York. Chartered in 1860 and first opened in 1867 as a competitor to the Long Island Rail Road, it was reorganized in 1874 as the Southern Railroad of Long Island and leased in 1876 to the LIRR. After a reorganization as the Brooklyn and Montauk Railroad in 1879 (immediately after which it was again leased to the LIRR) it was merged in 1889.