Complex sentence: Access to the Northern line platforms was indirect, its escalators connecting with the Piccadilly linefic from all three tube lines would have overcrowded the Victoria line escalators, Northern line trains ran through without stopping until repairs were complete.
Split into simpler sentences: Access to the Northern line platforms was indirect, its escalators connecting with the Piccadilly line. As the traffic from all three tube lines would have overcrowded the Victoria line escalators, Northern line trains ran through without stopping until repairs were complete.