New calculation of station ratings for aging wagons
Configuration file: newagerating
Command line: -Ya
TTD's station ratings depend on the age of the last vehicle transporting the cargo in question. For trains, this only regards the last wagon, for all other vehicle types, it's the vehicle itself. The rating will be highest if the vehicle is less than a year old, and will be lowest three years later. However, it is unreasonable to expect players to replace their vehicles far more frequently that every three years, or even to just replace the last train wagon.
Therefore, with this switch active, the maximum rating is maintained for the first five years, then it slowly drops to the minimum, which it reaches at the age of 21 years.
This patch was contributed by Csaba Varga.