Michael Portillo: World War I was a railway war. I'm going to find out how that railways helped to precipitate a mechanised war, defined how it was fought, conveyed millions to the trenches and bore witness to its end. I've taken to historic tracks to rediscover the locomotives and wagons of the war that was supposed to end all war, and to hear the stories of the gallant men and women who used them in life and in death.
