Factual error: James Franciscus arrives at a New York City subway station called Queensborough Plaza. Queensborough Plaza is an above ground station. Queens Plaza is the name of an underground station in New York City. (They are located within walking distance of each other, but are definitely distinct stations). (00:40:30)
Factual error: Brent enters the underground area via Queensborough Plaza. He and Nova walk some distance through (sewers?) and emerge outside the main branch of the New York Public Library, located on 5th Avenue and 41st St. in Manhattan. I'll concede that that's possible, since we don't really know how much tunnel they walked through. (It's about 2 miles and includes crossing the East River.) Only moments later, they're in front of the New York Stock Exchange, which is at 20 Broad Street, easily four miles to the south. In the next shot they're walking past Radio City Music Hall, on 6th Avenue and 50th Street. That's roughly a half-mile NORTH of the Library. I know stuff got shook up in the nuclear blast, but that's a bit much... (00:40:30 - 00:51:00)
Chosen answer: It's never explained. The ship had gone through a time warp and that may have rendered it inoperable once it arrived at the new time destination.
raywest ★