Illustrative renderings of the tunnel boring machines that will be used on the Hudson Tunnel Project. Image: Gateway Development Commission Manufacturing of the tunnel boring machines (TBM) that will excavate the New Jersey section of the Hudson Tunnel rail project is nearing completion, programme coordinator Gateway Development Commission (GDC) confirmed.

The first machine is 85% complete and the second 73%.

Both are expected to finish factory assembly by November before shipment to New Jersey, US, for reassembly. Each TBM measures 28-ft 8-in (7.8m) in diameter and extends 500 ft (15.2m) in length with gantries. Weighing 1,680 tons, the machines are equipped with more than 1,000 sensors to monitor underground positioning, wear on components, air quality, and other safety metrics.