Annie Mole The London Underground is an underground train system covering 11 lines. The longest line is the Central Line, which measures 34.1 miles, which is … eh, let me see… 55 kilometres. This line is also the most travelled. All the lines of the Tube, as the underground is nicknamed, carries more than a… Continue reading Let’s Go Tubing! – Bits and Pieces about the London Underground, Plus Quiz to test your vocabulary about metros