Between 1939 and 1945 war came to Britain's railways. By now an established technology, in the Second World War trains operating in Britain came into their own - bringing troops back home after the humiliation of Dunkirk, as well as taking hundreds of thousands of city children to safety. The programme interviews eye-witnesses to both railway adventures, and discovers the disused Tube station where the evacuations were coordinated. There are tales of the heroism of the railway staff during the Blitz, and how a small siding in a Hampshire railway station played its part in the preparations for D-Day.