In The Underground Challenge, you will compete against real Underground lines. The map starts with multiple lines already built, and you must try to beat the Underground's score. Much like the engineering crews of the London Underground, you must be quite resourceful at building track, and at the same time divert passengers to use your own lines, rather than the official ones. If you can beat the Underground at its own game before the Destination cards run out, you win The Underground Challenge!

This mini-expansion requires a copy of On the Underground: Paris / New York.