If you fill your whole city with 30+ story high rises and subways are overwhelmed even when running cars every 1-2 minutes (e.g. some Chinese cities), you can d

If you fill your whole city with 30+ story high rises and subways are overwhelmed even when running cars every 1-2 minutes (e.g. some Chinese cities), you can definitely create a bottleneck at the subway during commute hours. That's very high density we are talking about though.