IT’S a common hobby, searching for surviving pieces of the 1910 Pennsylvania Station, like ironwork, brass handrails and other fragments, amidst its vulgar replacement of the 1960s.

With Grand Central Terminal, opened in 1913, no such quest is necessary, but there is a network of fragments of what was conceived as Terminal City, a unified matrix of development atop the new real estate created when the tracks and railroad yards were covered. Much of Terminal City has fallen, although there is still enough left for the dedicated urban archaeologist.

In 1902, William J. Wilgus, an engineer for the New York Central Railroad, came up with the concept of roofing over the yards around Grand Central and building hotels, offices and apartment houses. Among the earliest concepts were a 20-story tower over the terminal itself, and an adjacent hotel, later erected as the Biltmore, from Vanderbilt to Madison Avenue, between 43rd and 44th Streets. In 1910, The New York Times published a design for a ceremonial Park Avenue showing tall, income-producing office buildings, but also new structures for the National Academy of Design and the Metropolitan Opera, their cultured imprimatur blunting the nakedness of the railroad’s commercial quest.

In the next 20 years, Mr. Wilgus’s plan remade the dozen or so blocks north of the terminal. The Biltmore was the best known, 26 stories high but set back along Vanderbilt Avenue to give the terminal breathing room. With no stores on Madison Avenue, a main dining room 120 feet long and a terrace on Vanderbilt, it was a particularly debonair work. Inside, the Palm Court had a timepiece on a wooden screen; “under the clock at the Biltmore” became a legendary meeting place.