They certainly were not soldiers, yet they suddenly found themselves in uniform, in a foreign land. But, as locomotive drivers, track-workers, conductors, porters, signalmen and engine cleaners, they knew how to run trains. And their job was to bring them back to life.

The Liberation Line tells the thrilling story of the British and American railway engineers who, in the months after D-Day, worked around the clock and in great danger to rebuild the ravaged railways of Europe and keep the Allied forces fuelled as they pushed on into Germany. As territory was taken, these soldier-railroaders were close behind, rebuilding the lines, putting up telegraph wires, replacing bridges and laying track, all the while dodging bullets, shells and booby traps.

Tales of extraordinary feats and heroism abound, including how 10,000 men rebuilt a 135-mile-long railway in just three days; the reconstruction of the bridge over the Seine in two weeks while under bombardment; and the use of cigarette lighters as improvised signalling systems.

Despite being critical to Allied victory, the role of the railwaymen has been largely forgotten or ignored. In a vivid and gripping narrative, Christian Wolmar brings to life this colourful cast of generals and engineers, without whose extraordinary bravery the liberation of France and invasion of Germany might well have foundered - and the course of history changed.