The steam locomotive was one of history's greatest inventions, and it revolutionised transport throughout the world. Huge numbers of individual steam locomotives were produced during the two centuries of its history, and in this series we see some of the greatest of them all - those built for the great original railway companies but which eventually went on to form the national British Railways. The East Coast of England and Scotland was served by the trains of the London and North Eastern Railway, on which ran the glorious A4s - the most famous steam locomotives of all time, and certainly the fastest! The title "greatest" must go to "Mallard", the fastest of them all, and "most famous" goes to "Flying Scotsman", both featured in this programme. But the LNER boasted many more great steam locomotives and here we see other A4s, include "Bittern", "Union of South Africa" and "Sir Nigel Gresley" - the latter named in honour of the gifted engineer who designed them. Many other locomotives were built to his designs and appear in this programme, including "The Great Marquess" and "Green Arrow", whilst his successors, Thompson and Peppercorn, provided designs such as the B1 mixed traffic and A2 Pacifies which are also seen here. We also see the maids of all work classes such as the J72 and N7 tanks and the Q6 heavy freight locomotives. These, and many others, are the great steam locomotives of the LNER.