Deep underneath South Kensington tube station, a huge project is underway to replace all five of the station’s escalators, and all of them at the same time.
To do that though, Piccadilly line trains have had to stop calling at South Kensington station and won’t call there again until next spring. Now, normally when escalators need replacing they don’t have to close part of the station, so why was this necessary at South Kensington?
Later it was decided to add deep level tunnels as well. The deep level tunnels were designed to have four platforms — two for what is today the Piccadilly line, and two for an unbuilt high-speed District line service between South Kensington and Mansion House with just one stop at Embankment.
It was designed so that there would be two eastbound platforms side-by-side, then under them, two westbound platforms, also side-by-side, so that swapping between lines would be easy.