PORTLAND – Amtrak’s Downeaster resumed normal service Thursday, a day on which the train ran at 79 mph for the first time.

The passenger train that runs between Portland and Boston reached the higher speed on a portion of track in Scarborough during the afternoon.

Other agreements reached with Guilford Rail System, which owns the tracks, will allow the speed to be lifted on other portions as well. Before Thursday, the top speed between Portland and Plaistow, N.H., was 59 mph.

For now, the track speed through Kennebunk will remain at about 25 mph while workers repair the Route 35 overpass, which buckled and forced a closure of the track last week.

Earlier this week, riders were taken by bus between Portland and Wells, where they linked up with the train.

Service resumed on the full length from Portland to Boston after debris was cleared in Kennebunk.