You're comparing a 4 lane highway to a 2 track rail? Crossrail in London will have a train every 2.5 minutes with a capacity of 1500 people per train. Trains

You're comparing a 4 lane highway to a 2 track rail? Crossrail in London will have a train every 2.5 minutes with a capacity of 1500 people per train. Trains also do not slow down to a crawl at high capacity.