In 1915 the railways of Britain consisted of 20,000 miles of track owned by 120 companies. The country could not support so many diverse and, in some cases, duplicitous operations and it was decided that they would have to be brought together into a neat bundle of just four companies to cover England, Scotland, Wales, and part of Northern Ireland. The Railways Act 1921, known as 'The Grouping Act', became law on 1 January 1923. After this, 120 separate...