They can’t because the game couldn’t cope with the amount of AI needed, causing it to lag. It’s the same reasons why Jamaica on LIRR sees about 3 trains a week.
I’m not sure about MSB but London Paddington sees 36 mainlines trains per hour in the peak which is probably more than any station on MSB
Maybe something like in WoS3 Circle Line where you can control the amount of passengers in the game settings...
Ai or geometry? passenger models are quiet detailed,(though they have LODs.) but their AI... well, what AI? lol. Or do you mean AI for Rail traffic?