I thought I remembered that there was a branch line beyong Epping to Ongar. There was. It was operated by steam until 1957 when the line was electrified, but the trains were only four carriages long. The loop at North Weald was closed in 1976. Blake Hall was officially closed in 1981, although drivers were apparently willing to make unauthorised stops on request. And the branch was finally closed in September 1994, so is no longer available to take the Cabinet to their nuclear bunker in Kelvedon. I find it odd to think how much the tube map has been quietly doctored during my lifetime without anyone, except maybe railway fanatics, and perhaps the Cabinet, noticing.