As much as its tunnels and trains, London Underground (LUL) relies on its escalators to keep the city moving. The 430 escalators on the network help passengers make more than 1.3 billion journeys every year. The longest, at 60 meters, is installed at Angel station on the Northern line, while its shortest cousin is a 4.1 meter baby at Stratford in East London.
Rail traction systems have undergone a change from the traditional use of DC motors to the use of more compact AC systems. These motors are lighter, require less maintenance, operate at higher speeds and provide
braking to stopping conditions; however they also carry the penalty of greater torque “ripples” and generate higher shock torques.