While I know this would reduce the realistic aspects of the game, I think it would greatly optimize the experience of players if elevators and the monorail were cutscenes rather than physical parts moving.
For example, elevators can be entered and a cutscene will be played of your player entering the elevator then it will play a cutscene of you exiting the elevator. The same would be done with the monorail except the monorail will load in and drive into the station, and players can click a prompt and their character will walk on and have their screen fade until they arrive at the next station.
This could already be a well optimized feature, but regardless I feel as though this would feel cleaner to the overall aesthetic of the game rather than the current system where your character will sometimes lag behind, fall through floors, etc.