The Connecticut Southern Railroad (reporting mark CSO) is a 90-mile (140 km) long short-line railroad operating in Connecticut and Massachusetts. The company was formed in 1996 as a spinoff of Conrail by shortline holding company RailTex and subsequently acquired in 2000 by RailAmerica. Since 2012, it has been a subsidiary of Genesee & Wyoming. CSO is headquartered in Hartford, Connecticut, site of its Hartford Yard. The company also operates East Hartford Yard.