The NYC Metropolitan Transportation Authority’s East Side Access project is spinning out of control, according to private contractors and engineering consultants building the rail tunnels from Penn Station to Grand Central Station and Queens.

As signs of trouble, engineers threatened to walk off the tunneling project last month, they say, and work was shut down on a large section of the project for four months earlier this year due too poor planning for the transition from one contractor to another.

The project completion date, originally set at 2013, is now estimated at 2021-22, they say. That’s about two years longer than MTA projections made five months ago.