ELLSWORTH, Maine — Lots of smiles, photos and thank yous marked a run of the Downeast Scenic Railroad on Saturday, a fine summer day in a long string of them that has helped the nonprofit excursion line continue to roll through its third season.

But the relaxed atmosphere created by the gentle rocking of the two coaches and an open-air car, passing busy High Street and then through a softwood forest and marsh area, belies the hard work that has kept the line up and running, said Tom Testa, the all-volunteer organization’s president.

“People don’t realize how much work this is,” he said, before quickly adding, “It’s a labor of love.” Testa and others launched the nonprofit in 2005, and the excursion trains began operating in July 2010.

Downeast Scenic Railroad leases 24 miles of the line that once ran from Brewer to Calais from the Maine Department of Transportation.

“We’ve only rehabbed out to Ellsworth Falls,” Testa said, for a total of five miles. Rehabilitation work includes replacing ties, some of which had nearly disintegrated.

“In the past four years we’ve installed about 6,000 ties,” he said. Work also included realigning rails, shoring up the stone bed and cutting back vegetation. The tree and brush cutting work never seems to end, he said.

A core group of 40 turns out to do the grunt work such as brush clearing, but also to maintain the train equipment, run the diesel electric engine, help people on and off the cars, act as conductors during the rides and hike out to the places where switches have to be manually thrown.

The organization operates on an annual budget of about $100,000 Testa said, with revenue coming from ticket sales, donations and grants. So far, “It’s paying its way,” he said. This summer’s fair weather and strong tourist season has helped.

“The weather’s been perfect,” he said, as 50 or so riders — young families and seniors — enjoyed the 10:30 a.m. trip Saturday. “It’s been going well,” with about 100 riders boarding each day.

The 90-minute ride begins at the small boarding facility behind Cadillac Mountain Sports on High Street, where tickets can be purchased for the weekend rides ($15 for adults, $8 for children ages 3-12), which began Memorial Day weekend and continue through Columbus Day weekend in October.

The train travels west for two miles, then heads back east, past the boarding area and continues three miles to Washington Junction. Here, riders are reminded of an important piece of history, which Testa believes many locals have forgotten.

In 1884, as Bar Harbor and Mount Desert Island began to draw wealthy summer visitors, a spur line was built to bring passenger cars to Hancock Point where the rusticators boarded a ferry to take them to the island. As many as seven trains a day traveled the spur at one time.

“The preservation aspect of this is a big reason why we wanted to do this,” Testa explained. Links such as the Brewer-to-Calais line were an upgrade from the weather-dependent schooners. “They made a lot of this [tourism] possible,” he said, defining the region even today.

Among the visitors on the train’s open-air car Saturday were Tara Libby and her daughters, Cassie, 10 and Breanna, 7 and their “Grandma Shepard,” who hail from Grand Isle, Vt. The family was on its way to an afternoon wedding in Bar Harbor, and decided to try a train ride. “I love history,” Cassie said.

Michel Brissette and Lucie Normand from Quebec explained that the train ride was part of their visit to Acadia National Park.

Susan and Tom Wentworth from Pembroke, along with their golden retriever, rode in one of the restored coaches. The trip was a birthday present from family for Susan, she said.

As the train traveled east through a pretty marsh area, a couple of ospreys were seen gliding overhead, and later, an eagle made slow circles over the train.

Riders hear the recorded voice of George Thomas, who on this day is the train’s conductor, describing what they are seeing and what areas they are passing. Thomas, who is operations manager at Bangor’s ABC TV affiliate, drove from his home in Corinth to help out. The narration is linked to a GPS so it plays at the right time, he explained.

Jonathan Murphy of Bucksport, who was on board to assist riders and answer questions Saturday, is another volunteer. “I’ve always been interested in railroads,” he said, and after riding the train last year, one of volunteers invited him to get involved. Murphy helps out three days a month, he said.

When the train returned to the boarding area, passengers filed past Thomas and Murphy, almost all smiling and thanking the men for the ride.

Trips at 10:30 a.m. and 1:30 p.m. continue on Saturdays and Sundays through Oct. 14, and on Labor Day Monday, Sept. 3 and Columbus Day, Monday, Oct. 8. For information, call 866-449-7245.