At the start of the game, each player only has one bus. Later, players may buy new buses. The maximum number of buses is defined as the number of buses owned by the player who has the most buses. This maximum number of buses determines the speed of the game. The larger this number, the more passengers, line expansions and buildings can be brought into play each round.

If every player has only one bus, the first player to choose new buildings may erect only one building; the second player to choose the action none at all. Later in the game, someone may have five buses. The first player to choose new buildings now has to build five, the second four, the third three, etcetera. Note that building actions are realised in a different order than the order in which they were chosen!