Currently Steam has the same City Comps as the other versions of the game but, especially in the early eras, they cause more problems than they create. It is highly unlikely that the President or Mayors want players hauling to the Cities due to a) the potential of levelling them out of synch with the LM during the comp and b) taking trains away from the LM after the comp because of the extra cash bonus.
Therefore instead of having a City Comp why not make it a Landmark Comp? The winner can be decided on an average/total of all goods delivered or a select few, such as the 5 goods with the highest tonnage. The subsequent cash bonus can then be applied to the Landmark.