This is the Indian sub-continent (British Imperial India) member of the18xxfamily of games. It is billed asA 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.
Dungeons & Dragons: Tyrants of the Underdark Boardgame (2021 edition)