Coming, skyscrapers over an active rail yard!

Here comes the next engineering marvel that would lift your living right into the sky - on a platform over the busiest commuter rail yard in the US.

A New York-based real estate developer is developing Hudson Yards at Manhattan's west side without footings or foundations.

Kicked off last week, the project is being built atop 300 concrete-sleeved, steel caissons jammed deep into the underlying bedrock.

Caissons are watertight retaining structures used in bridge building as foundation.

The engineers would drill them anywhere from 40 to 80 feet into the Manhattan schist - the dense, metamorphic bedrock that supports the city's soaring skyline.

The caissons would be meticulously arranged in the narrow spaces between the train tracks.

Above, they would connect to deep-girdle trusses - some up to eight stories tall - that control and redirect the towering weight overhead.

"The total weight is somewhere near 35,000 tonnes of steel and 50,000 cubic yards of concrete," Jim White, the lead platform engineer from Related Companies, a privately-owned real estate firm in New York City, was quoted as saying.

"We look at the train traffic and actually design the connections so we can install these 100-foot-long trusses when have a window of opportunity," White added in a report in Wired.com.

There are plans to build a four-acre green boulevard that would extend from the north of Hudson Yards through Hell's Kitchen and would end in Times Square, the report added.

Hudson Yards, at a planned 17 million square feet, is the biggest private real estate development in the US history.

The Hudson Yards Redevelopment Project is a joint venture by New York City Department of City Planning and Metropolitan Transportation Authority.

According to Related Companies, the entire project would be completed in 2024.