New York's most fascinating park, The High Line, is set for a grand expansion, and FastCompany.com got a hold of the first images of what the new section of the park will look like.

Currently, the High Line occupies an all-too-short, re-purposed stretch of elevated rail line from 14th Street to 20th Street. The second phase, which will be completed by next spring, expands the park dramatically from 20th street to 30th. The designers, James Corner Field Operations and Diller Scofidio + Renfro, seem to have saved the park's very best features for the new section.

Above: What the designers are calling a "spur," a seating area overlooking 26th street. The viewing frame that defines the space is meant to recall the bygone billboards that once attached to the railway.

To see the new features being added, skip to 1:55:

Below: At one point, the designers will strip away the concrete deck of the High Line, revealing the girders that support the entire structure. Visitors can "float above" on a viewing platform:

The High Line will get it's very own version of Central Park's wild and woolly Ramble--a dense stretch of trees and shrubs called the Chelsea Thicket:

The plantings have been carefully thought out--most are species that grow naturally, but they've been interspersed with other plantings, so that each stretch always has something in bloom during growing season:

A new access point at 30th street:

Maybe the park's grandest feature, a "flyover" where the walkway rises above the High Line's level, and into the shady canopy of sumac trees. The plants fill in the emptied space below, and to adapt to the shade cast from overhead, they've been selected from the among plants that naturally grown in the shadows between New York's tall buildings:

The High Line will also finally get a nice lawn for lounging, and bleacher seating too: