Platform screen doors for the Tube, National Rail and DLR

Platform screen doors are doors that prevent lunatics by falling, jumping or slipping to the tracks.

Heights
There are two heights. Half-height doors are not installed and the full-height doors are installed at five meters on all stations. =How many doors= There are eight hundred thousand, eight hundred full-height automatic doors altogether.

Examples
Central Line Circle Line, District Line, Hammersmith & City Line and Metropolitan Line Northern Line Victoria Line Waterloo & City Line London Overground