mapsofindia.com

[GWR]

http://www.mapsofindia.com/
http://www.mapsofindia.com/railways/index.html
Clickable rail map (http://www.mapsofindia.com/maps/india/india-railway-map.htm)
http://www.mapsofindia.com/maps/assam/railways/dibrugarh.gif

[GWR]

http://www.theodora.com/maps/new9/indian_railways_map.jpg