Watch | A look into the futuristic train terminal being built under NYC

One of the nation's largest transportation projects is rolling forward — a Manhattan commuter rail terminal accessed through a tunnel costing $1 million per foot.

That detail was offered Wednesday by the head of capital construction for New York's Metropolitan Transit Authority. The terminal will allow the MTA's Long Island Rail Road passengers to get off on Manhattan's East Side at Grand Central Terminal.

When completed, the $10 billion East Side Access will bring 160,000 passengers daily from Long Island through a Queens station linked to the 120-foot tunnel. The target completion date is 2022.