How the invention of the railway at the dawn of the 19th century changed the world, and the lives of engineers such as Stephenson, Telford and Brunel. Though great wealth was made on the back of steam power, many rail lines couldn't break even and huge swathes of them were eventually axed from existence. Cameras also reveal how Britain's railways are on the move again as HS2 plans to connect the most influential cities with their own high-speed, high-capacity rail line