Construction recently began on an $8.7 billion New York to New Jersey tunnel, the largest U.S. transportation project that is expected to double the number of rail commuters traveling between New Jersey and Manhattan.

The new tunnel will add two more rail lines and will help to speed up the work commute by increasing the number or NJ Transit passenger trains under the river during peak rush hour from 23 to 48. In some cases, traveling time will be cut down by 15 minutes each way because commuters will no longer have to switch trains to reach Manhattan.

Peter Rogoff, chief of the Federal Transit Administration said that the federal government’s $3 billion contribution to the project is the largest ever by his agency and that the tunnel will shorten rail trips in New York City and northern New Jersey, which have some of the nation’s longest commutes.

The new tunnel is estimated to create 6,000 construction jobs and 45,000 permanent jobs upon completion. The project is expected to be completed in 2017.

This story originally appeared in Engineering News-Record.