The Sprinter revolution of the 1980s led to the mass withdrawal of British Rail's vast fleet of first generation Diesel Multiple Units. However, a need was identified for a small number of DMUs of certain classes to be kept on beyond their notional lifespan, under the official title of heritage units. Some of these units later made it through the privatisation process and into the twenty-first century. In this book, Roger Marks looks at the heritage units used by First North Western, Scotrail, First North Eastern, Silverlink, Chiltern Railways, Arriva Trains Wales, South Central and the units that went into departmental service. In addition to some superb shots of the heritage units, he also takes his camera inside the cab and saloon interiors, as well as exploring the technical side of the DMUs.