Britain has around 180 preserved, or heritage, railways -- lines operated for their historical interest. They carry 13 million passengers a year and are operated by 22,000 volunteers. Seldom has there been a bigger spontaneous exercise in turning back the clock. In this book, Andrew Martin seeks to discover why the British are so keen on old railways. He rides the lines and meets the Preservationists. Some subjects arise repeatedly: not least Thomas the Tank Engine, the railway axeman Dr Beeching and, most pressingly of all, the question of whether preservation can survive the passing of 'generation steam'.