This is the story of the men who set out from Britain to build railways worldwide. Some were part of Britain's grand imperial progress, tying together the Empire with threads of iron. Others represented a no less potent economic imperialism, building lines with British capital and manpower, keeping British industry busy supplying everything from rails to powerful locomotives, and taking the profits back to Britain as well. The great men of the railway age all play a part: Brunel worked in Italy, Robert Stephenson built a great bridge across the St Lawrence at Montreal and Joseph Locke supervised some of the first railways in France. But the story recalls, too, the heroism of the less well known, labouring in uncharted, hostile terrain against seemingly impossible odds: against man-eating lions, dense jungle, and plains which flooded dramatically in the wet season, precipitous mountain ranges, and inevitably disease. Conditions like these produced personalities to match - men like the contractor George Pauling who built lines throughout Africa, and whose party trick was to run round a billiard room with a pony on his shoulders. Finally there were those who did the hard labour itself, the tough experienced navvies, capable of prodigious feats. A Frenchman seeing them on the Paris to Rouen Railway exclaimed, Mon Dieu! les Anglais, comme ils travaillent. No country rivalled Britain in spreading railways across the globe, and yet inevitably within this phenomenal success lay the seeds of decline. The benefits of local labour, materials and experience began to outweigh British expertise. The legacy of immense achievement, however, has long outlived the days of empire.