The Metro-North Railroad says service will resume along the length of the Port Jervis line by Nov 28.
The line serves about 2,300 riders a day in Rockland and Orange counties. It was heavily damaged during the aftermath of Hurricane Irene.
Buses have been replacing trains in areas where tracks have not been repaired.
The original target date for full service on the Port Jervis line was the end of December. But Metro-North officials said Monday that the repairs will be completed one month ahead of schedule.
Metro-North also said the cost estimate of up to $60 million has been cut to $30 million to $40 million.
Compared to the pre-storm schedule, running times for Port Jervis line trains will be slightly longer to accommodate continuing track work.