Metro

20K would ride NY-NJ 7 train

The long-discussed extension of the 7 train to Secaucus, NJ, would draw 20,500 Manhattan-bound commuters every morning, a new study says.

It’d be a speedy trip — eight minutes to the West Side, 12 minutes to Times Square and 16 minutes to Grand Central Terminal, says the engineering report commissioned by the city.

But the MTA rejects the plan. “We don’t see this as an economically viable idea,” it said in a written statement.

Amtrak is also studying new rail tunnels from New Jersey to New York. The tunnels now linking Jersey and Penn Station are more than 100 years old.