In this five part series, Michael Portillo marks the centenary of the First World War by discovering the central role the railways played in securing victory, repatriating the dead and wounded and feeding the insatiable appetite for weaponry and supplies that the theatre of war demanded. This is a story of how a British invention that brought trade, travel and prosperity in peacetime became an engine of war. Michael tracks down the fascinating, emotional and sometimes tragic stories of the wartime railways that criss-crossed Britain and Europe. They were the crucial new arm of modem warfare at a time when motorised transport on the roads was in its infancy. Over the five episodes Michael travels to the key railway locations that would become synonymous with the victories, defeats, battes and campaigns of the First World War, showing how integral they were to our success, often in surprising ways and how they helped to shape the Europe we know today.