The scale is like something out of an Indiana Jones movie. The yellow cladding is a waterproofing geotextile that will soon be covered over itself as the cavern is turned into a terminal.
The titanic yellow facility—its walls secured behind waterproofing geotextiles that will, of course, eventually be covered over altogether, meaning that this surreal yellow scene is just a temporary state—is on the Grand Central side of the project, and will be part of a huge new underground terminal increasing access for the Long Island Railroad. It is also just one of the many other, ongoing workstunneling away beneath the surface of the city.
Typos courtesy of my iPhone