20th Century Limited is driven by one mechanic being utilized in two different ways. Today I will discuss the Regional Rail Cards. This mechanic will be the most familiar to all players and the most easily understood by non-gamers and casual gamers. It is as simple as connecting the dots.
The game progresses over eight eras, from the earliest beginnings of rail transport on the eastern seaboard to the plains, off to the west coast and the great northwest. As players fulfill their Regional Cards in order they will create a network of track spreading westward across the board. Each player knows in advance which eight cards they will have to fulfill and can plan their game accordingly.
Regional cards are completed simply by connecting the three cities listed on the card with one contiguous route. It is very akin to the Trans America system except that each player uses only their own set of tracks. In some ways that mechanism is even easier to explain than the system of shared tracks Trans America. Instead of the game or round ending when one card is completed, players proceed to the next Region Card and begin working on that one. If one player completes all eight of their Region Cards, the game ends.
Scoring for the regional cards starts out slowly, 3 points for the first card, 9 for two, 21 for three... If you manage to finish all eight of the Regional Cards you will receive 126 points. So sticking with it can pay off really big in the end.
Thematically, the placing of links on the board to complete Regional Cards represents the individual rail barons starting small independent rail lines that cater to the demands of local interests. Each Region can be stand apart from the others but an earlier route can later be expanded to service additional regions.