PORTLAND – About 45 people who have been upgrading the railroad tracks for Portland-to-Boston passenger trains are losing their jobs, but the layoffs are not expected to affect the start of the rail service.

The track preparation is nearly completed and the long-delayed service is expected to start running in late summer or early fall.

As a result, an estimated 45 people who have been working on the tracks will lose their jobs, said David Fink, executive vice president of Guilford Transportation, which owns the tracks.

Fink said he expects the track work to be completed by mid-July, and for the track crew to be reduced from about 80 employees to about 35.

Fink said he anticipates that many of those losing their jobs will be reassigned to other positions with the company.. Jonathan Carter, chairman of the Northern New England Passenger Rail Authority, said the part of the line still needing work is in Portland.

Meanwhile, work will begin soon on the platforms where the train will stop in Portland, Saco and Wells. Operating agreements outlining who will operate the stations are being finalized, said Peter Murray, executive director of the Northern New England Passenger Rail Authority.