New York City’s most expensive transit project just keeps getting more expensive. And it has nothing to do with fixing the failing subway.

A new train station under Grand Central Terminal and a tunnel connecting it to the Long Island Rail Road will now cost more than $11 billion — about $1 billion more than a 2014 estimate, according to the Metropolitan Transportation Authority. The project is unlikely to open before December 2022.

The compounding cost overruns and construction delays on a project that began more than a decade ago have raised doubts among city leaders over whether transit officials can tackle an ambitious overhaul to rescue the subway, which serves many times more riders than the new train station will.

The rail project, known as East Side Access, would bring the Long Island Rail Road to the East Side of Manhattan — the commuter railroad currently uses Pennsylvania Station on the West Side. An investigation last year by The New York Times found that the costs for the project were likely to surpass $12 billion, or nearly $3.5 billion for each new mile of track, seven times the average cost in other cities across the world.