The Staten Island Railway (SIR, formerly SIRT) is a rapid transit line operating in the Borough of Staten Island, New York City, USA. It is considered a standard railroad line, but is currently disconnected from the national railway system and operates with modified R44 New York City subway cars . The current SIR line has been completely grade-separated from intersecting roads since 1966. There are no links between the SIR and the subway system proper.