Originally Posted by rkkwan
Anyways, I'm most impressed by NYC's 4-track layout with express trains running in the middle. Cuts a lot of time between stations between Mid-town and Downtown.
Express tracks are a US phenomenon. Very relevant in New York where the city is long and thin, they are also on the systems in Philadelphia and Chicago (except may I ask if the express tracks in Philadelphia on the Broad Street line are now abandoned ?).
The New York station at 34th and Broadway, with two 4-track routes crossing one on top of the other at an acute angle inside a huge tunnel chamber, is indeed impressive engineering, there are other similar ones. You can just about get to a position to see the whole thing from one point.