As in other Ticket to Ride games, in Ticket to Ride: Rails & Sails players start with tickets in hand that show two cities, and over the course of the game they try to collect colored cards, then claim routes on the game board with their colored train and ship tokens, scoring points while doing so. When any player has six or fewer tokens in their supply, each player takes two more turns, then the game ends. At that point, if they've created a continuous path between the two cities on a ticket, then they score the points on that ticket; if not, then they lose points instead.
Ticket to Ride: Rails & Sails puts a few twists on the TtR formula, starting with split card decks of trains and ships (with all of the wild cards going in the train deck). Three cards of each type are revealed at the start of the game, and when you draw cards, you replace them with a card from whichever deck you like.