The broadcaster returns, beginning by travelling across Europe to examine the train's role in the First World War. In Northumberland, he enjoys a ride on a preserved locomotive to find out how important the railways were to Britain for mobilisation of troops and the operation of large training camps around the country. Aboard a holiday train commandeered to transport troops and ammunition, Chris tells the stories of two opposing soldiers, one English and one German, who both took trains to the Somme in 1916.

• Chris Tarrant