From what I could grasp the four loudest lines were also some of the most well used: the Central line, the Northern line, the Jubilee line and the Victoria line.
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Revealed: These are London's most overcrowded Tube linesStatistics from mayor of London Sadiq Khan show that morning peak hour capacity on the London Underground is more than 100 per cent, with the Northern, Central and Jubilee lines the most crowded.