the underground challenge paris new york expansionNOTE: This mini expansion requires a copy of On the Underground: Paris New York. 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 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.