Is there a bonus card (either longest route or globetrotter) when playing the Ticket to Ride USA 1910 Expansion in Big Cities mode? There is no mention of it in the rules. Is this an oversight?
I believe that you don't use either bonus card in the Big Cities version of the game (as it's not suggested that you should in the rulebook).
This interpretation is backed up by the computer version and the ruleset found in the computer version, which don't use a bonus card.