The view from the train tells the story of this part of rural southwest Georgia: cotton fields speckled with puffs of white; peanut and soybean fields; groves of towering pecan trees. Rusted old cars that appear to have been parked in the same spot for decades. Gullies filled so thickly with kudzu that it ripples and flows like a river’s eddies and currents.

Then we roll into Plains, population 683, which looks frozen in the time of Jimmy Carter’s presidency. The historic train depot, closed in 1951, was Carter’s campaign headquarters in 1976 and now is a museum that focuses on that campaign. A big sign painted above a storefront in the tiny downtown shouts that this is the home of the 39th president of the United States. Jimmy and Rosalynn Carter still live here in the same house that they have owned since 1961.

I’m riding a SAM Shortline excursion train on a day trip that starts at Lake Blackshear on the western edge of Cordele, Ga., southwest of Macon, and runs west about 50 miles, then returns. This 6 1/2-hour excursion goes to Plains, where we spend nearly two hours exploring the town, then Archery, the boyhood home of Carter and now a site managed by the National Park Service. On other days, the train has different itineraries along the same track.

The track dates to the Savannah, Americus and Montgomery line of the late 1800s, which is where the SAM Shortline Excursion Train got its name. Cordele and Plains are among the towns that sprang up along the rail line when it was new.

The track had been in decline and was in danger of abandonment when the state bought it in 1999. The state parks division runs the excursions along with the Heart of Georgia Railroad — a private company that owns the engines — and the Southwest Georgia Railroad Excursion Authority, a state agency.

The locomotives are modified EMD GP-9s, diesel-electric locomotives built by General Motors in the 1950s and early 1960s. Most of the passenger cars date to the late 1940s and the Norfolk and Western and Pennsylvania Railroad and were later used as commuter trains by the Maryland Area Rapid Commuter Agency. One of the most historic pieces of equipment is the “Samuel H. Hawkins,” a 1939 tavern-observation car that was named for the founder and president of the Savannah, Americus and Montgomery line.

We board the train at the Georgia Veterans State Park. The train is run by two Heart of Georgia Railroad engineer/conductors, but most of the people who welcome us aboard and answer questions during the ride are volunteers.

The train crosses the bridge over Lake Blackshear. Clusters of caladiums grow along the water line and cypress trees grow in the water. It is the end of September, and the first bits of fall color are just beginning to peek through the green of the oaks and maples. We pass stands of evergreens, fields of goldenrod, bales of picked cotton waiting to be picked up.

A stretch of track runs past ramshackle houses, where junk is strewn across the ground and old cars are slowly falling apart, past small industrial areas, and gracious homes in Americus.

Today’s excursion is built around the Jimmy Carter National Historic Site, which stretches from Plains about three miles west to Archery, and includes the train depot; the former Plains High School, which is now a museum and visitors center; and the farm in Archery, where the future president grew up.