(Source: New York Times, October 14, 2015)
NEW YORK — Rivaling the U.S.S. Intrepid in length, but invisible to passers-by or office workers looking out their windows, parallel twin tubes now stretch from 10th to 11th Avenue, just west of Pennsylvania Station. Two stories tall, each of the tubes is large enough to accommodate an Amtrak or New Jersey Transit train, which is what they are intended to do some day in the future.
Full story: New York Times