Almost forty years ago, when steam trains had precipitately vanished, along with a third of Britain’s entire railway network, stations and shunting yards, I wrote an article for a Sunday magazine called ‘The Down-Train to Childhood’. It centred on a Sussex branch line, by then axed, that I had known in the early 1950s. I had put ha’pennies on the rails to get them squashed into pennies, watched milk churns expertly hauled in and out of the open guard vans of slowly moving trains, and scared myself enjoyably by standing close to the track when a squat, black tank engine came puffing down. (I’m sure it scared the drivers too. They used to hoot at me, which I took for a cheery greeting.) Back then, they were commonplace experiences. Now they are unimaginably remote.