Add each new building tile to the existing building tiles of its color.  This promo comes with four identical 13a/b building tiles, one in each player color.

13a: Discard exactly one gray cattle ("Jersey") and perform one single auxiliary action. Perform the action "Place one of your private buildings onto a building space on the trail". For each craftman needed for that building tile, you must pay 1 Dollar.

13b: Gain twice as many Dollars as you have discs on train stations. Perform one single or one double auxiliary action.