Michael Portillo's postwar exploration of Merseyside to Teesside finds him in York, a paradise for rail enthusiasts. In the company of some of the most famous locomotives ever built, he recalls the controversy surrounding their relocation from London to a freight depot in York.Michael crosses the magnificent Knaresborough viaduct, with its castellated walls and four beautiful arches over the River Nidd, to reach the spa town of Harrogate. On the edge of the elegant town, Michael discovers the gardens at Harlow Carr and learns how they opened in 1950 to test growing conditions for plants in northern climes.Across town, Michael checks into the headquarters of Yorkshire Tea. And his last destination on this leg of his journey is a bog near Skipton. In the 'gateway to the Dales', he joins members of Yorkshire Peat Partnership to find out what makes a bog.