It is a loop, but passengers are not allowed on that segment. If you manage to stay on the car, you also get to take a quick peek at an abandoned station.
Ahhh, yea, in that case I believe the bottom of the 1 is as well in the Financial District. Very small loop. Always interesting to get on there because I think it's the tightest curve I've found and the trains probably at a good 6 or 7 degree tilt there. Neat stuff.
