The British Rail Class 379 Electrostar is an electric multiple-unit (EMU) passenger train designed and built by the rolling-stock manufacturer Bombardier Transportation. The trains are part of the company's extensive Electrostar family. Since their introduction during early 2011, the Class 379 became the principal type operated on the Stansted Express service; it was also tasked with additional services between London Liverpool Street to Stansted Airport, Cambridge and Kings Lynn. The fleet was initially operated by National Express East Anglia (NXEA) and subsequently by Greater Anglia.