The Amtrak Downeaster will transport passengers on buses between Brunswick and Wells for about six weeks this fall as workers replace railroad ties on about 30 miles of track.

The use of buses is intended to avoid service interruptions and late trains that plagued the Downeaster during a tie replacement project last year, said Patricia Quinn, executive director of the Northern New England Passenger Rail Authority.

Also, one of the Downeaster’s five daily round-trips will be suspended during the work and there will be no service on two weekends in October and November because of track construction and bridge work in Massachusetts.

The inconveniences will undoubtedly turn passengers away, Quinn admitted.

“It is definitely going to have an impact on ridership and revenue,” she said. “We’ve planned and budgeted for that.”

However, a relatively brief service disruption is preferable to a months-long nightmare of delays and cancellations the service experienced in the past two years, Quinn said. From July 2014 to June 2015, only 30 percent of Downeaster trains arrived on time, mainly because of a massive construction project to replace 30,000 railroad ties on a 78-mile section of track. The Downeaster tried to schedule trains to avoid construction, but ended up with hourslong delays and canceled trains instead. The problems were exacerbated by a long, cold winter and construction delays.

This year, the Downeaster recovered from that setback, with 81 percent of trains running on time in April, May and June, an August report from the rail authority said.

About 15,000 ties on 30 miles of track between Portland and Wells will be replaced this year. Instead of trying to schedule around the construction, rail authority staff opted to use buses to transport passengers. Busing is a common way to replace train service during interruptions such as construction, Quinn said.

“The fact that we are going around all the construction is much better,” she said. “It is inconvenient, but it’s not some horrible crazy thing that doesn’t happen anywhere.”

Starting Oct. 11, Downeaster passengers from Brunswick, Freeport and Portland will be bused to and from the Wells station, where they will board trains for Boston. Passengers between Saco and Wells will be taken in a van. The bus service will start five to 15 minutes earlier to make sure the train from Wells is on time, Quinn said. Busing is expected to last until Nov. 21, when the Downeaster will release a new service with three round-trips a day between Brunswick and Boston, Quinn said.

A midday service between Boston and Portland also is being suspended during the tie replacement. Trains 683 northbound, at 11:26 a.m. and 684 southbound, at 12:40 p.m., and equivalent weekend trains, 693 northbound and 694 southbound, will be taken off line. There isn’t typically a lot of demand for those off-peak services, Quinn said.

To complicate matters, the Massachusetts Bay Transportation Authority is working on bridges over the Merrimack River over the next two months, and will be busing train passengers between Haverhill, Massachuestts, and Boston on Oct. 8-9 and Nov. 19-20. The Downeaster will not run any trains on two weekends, Oct. 22-23 and Nov. 5-6, to avoid busing passengers for most of the trip, Quinn said.

Downeaster passengers will be compensated with reduced fares during the construction period. One-way tickets between Boston and any of the stops north of Wells will cost $17, the cost of the Wells-Boston trip, Quinn said. A one-way ticket on the Downeaster from Boston to Portland now costs $25, or $34 for business class.

Because bus space is limited, passengers should make reservations well in advance, Quinn said.

“This is not a good time to show up without a reservation,” she said.