Amtrak is suspending two midday trips on the Downeaster and modifying service on two more trips to accommodate track work through Sunday.

Modified service on the 681 and 686 trains, will include a “combination of trains and charter busses,” and neither will stop at Saco or Old Orchard Beach, the Downeaster said in a service announcement.

The Downeaster pulling into the Brunswick Visitors Center. Service on 4 of the line’s 10 daily routes is disrupted from Aug. 18-25. C. Thacher Carter/The Times Record

The 681 is the line’s first northbound train, leaving Boston at 8:50 a.m.; the 686 runs southbound from Brunswick and departs at 12:55 p.m.

Meanwhile, two midday routes are completely suspended for the week.

Train 683, which heads north from Boston at 11:50 a.m. and arrives in Brunswick at 3:10 p.m., and train 684, which leaves Brunswick at 11 a.m. and arrives in Boston at 2:20 p.m., are canceled with no alternate service options.

The remaining six trains will run on their usual schedule. Detailed route information is available on the ticketing website.

The service changes are intended to allow crews to complete work on the Wells Area Improvement Project, Amtrak said. That project includes extending the existing strip of passing-lane track and building a new platform.