Well, 2.5 million people use the London Underground every day, with opening hours being between 5:30am and 1am. That's eighteen hours, give or take. of course, it's not fully laden for that entire duration - the bulk of passengers travel in the rush hours, between 7am-9:30am and 4:30pm-6:30pm.
So a reasonable estimate would be that the London underground can move two million people in about four hours. that's 500,000 people per hour, at capacity.
all of which means that the Sansha dropship force, not accounting for losses from engaging the navies in low orbit, would be a logistical undertaking four or five times the size of the Tube.