The Southwold Railway opened in 1879 and closed in 1929. It was a 3 foot narrow gauge line in Suffolk that linked Southwold and the sea with Halesworth on the main Great Eastern line 9 miles away. In 1966, a surprising amount of the Southwold terminus was still (more or less) standing. Some of the trees in the background can be seen on period photos of the line, albeit rather smaller!
If open today, it would make a mint as a tourist attraction line. But it’s not been forgotten. The Southwold Railway Trust work to keep memories of the line alive, with the long term aim of running trains again on at least part of the original track bed. Their site includes this excellent map of the line.
My main memories of that family holiday were walking the old line from Southwold and finding the old loco shed still standing, looking out of my bedroom window and seeing a Pied Flycatcher on the tree outside, and returning home early as my paternal grandfather had died unexpectedly.