When a player lands on a railroad, the player needs to pay the owner 50 * (number of railroads), however, the number of railroads is only for non-mortgaged railroads. For example, player red lands on B&O, owned by player Green. Green owns all four railroads, but mortgaged Pennsylvania Railroad. The total owed to player Green by Red should be $150, not $200. Currently the game charges player Green $200.