When it is completed at the end of 2018, the project will dramatically increase capacity on the 29km stretch between Farmingdale and Ronkonkoma, enabling LIRR to improve reliability and provide more frequent off-peak services in both directions.

LIRR has awarded a Skanska-Posillico joint venture a contract worth up to $US 59.7m to carry out track-doubling on two sections between Farmingdale and Central Islip totalling 11.9km. Civil works being are already nearing completion on the adjoining 8.4km Central Islip - Ronkonkoma section.

Under the second contract, which is worth $US 44.8m, Ansaldo STS will design, build, and commission a new signalling system, which will improve operations on the branch when the track-doubling project is completed. The project includes new interlockings at Farmingdale, Wyandanch, Deer Park and Central Islip and a modified interlocking at Ronkonkoma.