RAILWAYS

US
https://en.wikipedia.org/wiki/Rail_transportation_in_the_United_States
WORLD
https://en.wikipedia.org/wiki/List_of_countries_by_rail_transport_network_size
INDIA GEOWTH
http://www.yourarticlelibrary.com/railways/indian-railways-development-factors-distribution-and-improvement-of-indian-railways/14134/