You can’t 3 star the scenario [A2] 7. Football Special in the dlc “South Western Main Line: Southampton Bournemouth Route Add-On” because you will always be between 3 to 5 minutes late thanks to the 75 mph speed limit. It seems that the timing and the speed limit aren’t synced up properly.
They are set like arcade games because people, like yourself, wish to say they have scored some points. If the Scenarios were easy to complete then everyone would get a full score and make them pointless