The site's 200-acre size is both a draw and a challenge, according to Christopher Jones, vice president of research with Regional Plan Association, who said they were "very glad to see the mayor put this on the table." "There's almost no place left in New York City where you can look at an area that large, that could potentially support so many of the things the city needs," he said. "The challenge, of course, is that in order to build over an active rail yard of that size, it is going to be incredibly expensive." It could take years, likely more than a decade, for a project of this size to get off the ground, experts said. "The history of large development projects in New York is they have to go through several iterations before they're actually built," Jones said. "That’s why its really important to get this discussion going now." Read the full article in DNA Info.