The British Rail Class 230 or D-train is a planned Vivarail design diesel electric multiple unit to be built for the British rail network. The units will be converted from London Underground D78 Stock.It is proposed to run 75 units of two or three cars per unit. They will become known as Class 230 under TOPS. The prototype was produced for testing and accreditation in August, with introduction to service in 2016. They are to be tested in mainline service on the First Great Western network.