Into the Big Apple's core: New images reveal massive Grand Central-style subway station being built in New York

When completed in 2019 the tunnels will bring subway and commuter rail services to under-served stretches of New York

While the rows in the UK over Crossrail and the future of the HS2 project continue, over the pond  the Big Apple is once again showing a bold approach to infrastructure projects as 16 stories under Grand Central station a new rail track is being tunneled out of solid bedrock.

The project is part of a typically audacious plan for three new underground rail routes which will cost $15bn (£9.57bn) and will span 14 miles throughout New York.

An army of workers have already blasted enough rock from beneath New York to cover Central Park almost a foot deep.

When completed in 2019 the tunnels will bring subway and commuter rail services to under-served stretches of the city, particularly the far East and West sides of Manhattan.

Perhaps the most ambitious part of the plan is to create the equivalent of a Grand Central Terminal underground, mirroring the century-old building above.

The dimensions of the future eight-floor concourse are about 70ft (21m) wide and 1,800ft (550m) long.

Remarkably, despite the blasting and drilling beneath them New Yorkers seem untroubled by what is going on in the miles of tunnels and gravel-filled pits beneath the surface.

Engineers have had to use creative solutions to deliver the three mammoth projects, and have employed the latest technology.

Tunnels have been coated with a material once used to fireproof the space shuttle.

The new line also uses air cooling plants, instead of ventilation grates.

When attempting to drill a giant new cavity under Second Avenue engineers first had to freeze the ground to minus 20 degrees Fahrenheit (minus 29 Celsius) in order to avoid destabilising the buildings above.