This is the Indian sub-continent (British Imperial India) member of the 18xx family of games. It is billed as A game for engineers who've had enough of the financiers! It involves five-foot-six and metre gauges, hills, mountains and the Himalayas, contract bids and government mails. The technical challenges of building a railroad network in difficult country stand on a par with the financial market manipulation which usually dominates the 18xx games.
Time to play is listed as 4-7 hours. Ages 11+. A 4-hour game would be an exception and it's not really for 11-year-olds.