The Go-Ahead Group is a passenger transportation company. The company organises itself into three segments: regional bus, London bus, and rail. Rail, which contributes the majority of revenue, transports passengers by rail through a joint venture under the Southern, Southeastern, London Midland, and GTR franchises. London bus, the next most significant segment, operates bus and rail replacement services in London. The regional bus segment operates bus services in the United Kingdom outside London. The Go-Ahead Group is headquartered in the U.K., and derives revenue domestically.