AEV Design:
https://www.cnn.com/travel/article/world-best-metro-systems/index.html
http://www.explainthatstuff.com/gears.html
Direct Drive Train:
https://en.wikipedia.org/wiki/Direct_drive_mechanism
AEV Design:
https://www.cnn.com/travel/article/world-best-metro-systems/index.html
http://www.explainthatstuff.com/gears.html
Direct Drive Train:
https://en.wikipedia.org/wiki/Direct_drive_mechanism