No real estate developer has profited more from the High Line than Related Companies, the global giant.

Under its chairman, Stephen M. Ross, Related has, in recent years, become the biggest luxury developer in the neighborhood by a wide margin, erecting buildings designed by Zaha Hadid, Thomas Heatherwick, Robert A.M. Stern, among other marquee names, and last year completing the first phase of Hudson Yards, the largest mixed-use private real estate venture in American history.

A blue-glass megadevelopment with a supersized shopping mall and trash-basket-shaped tourist attraction called the Vessel, by Mr. Heatherwick, Hudson Yards rose from a massive deck that Related built atop a dozen acres of working rail tracks where the High Line jogs west from 10th Avenue along West 30th Street toward the Hudson River.

Now Related is undertaking phase two of Hudson Yards, the Western Yard. It is conceived to bring millions more square feet of towering private, high-end office and residential construction to the neighborhood. In return, Related has promised a new public school. The project will deck over the remaining acres of open tracks between 11th and 12th Avenues, from West 30th to West 33rd Street, a vast property bordered on the south and west by the High Line, which turns north from West 30th Street at 12th Avenue.