“We’ve had people come from as far as Pennsylvania, a seven-and-a-half-hour drive, because they saw this online and wanted to try it,” said Mary-Joy Lu, who, along with her husband, Alex Catchpoole, owns Rail Explorers. “We thought we’d start slowly with five or 10 people per tour. Since we opened, it’s been booked every day, every tour. After the first month, we doubled the fleet from six to 12 rail bikes.”

Ms. Lu and Mr. Catchpoole, who used to live in Brooklyn before moving here to start their business, said the success of the rail bikes, which started this year, had fueled their bigger goal of forming partnerships with historic rail lines in other parts of the country.

But before that can happen, the couple may have to relocate their business.

The track is part of 119 miles of state-owned rail corridor between the town of Remsen and the village of Lake Placid. The railroad opened in 1892 and is listed on the National Register of Historic Places.

A recent draft report by the State Environmental Conservation Department and the State Transportation Department calls for converting a 34-mile section of track into a recreational trail from Lake Placid to Tupper Lake. It would include the section that runs through Saranac Lake. The multipurpose recreational trail would primarily be used by cyclists in the summer and snowmobiles in the winter.

“All of those communities have endorsed a recreational trail,” said Jomo Miller, a spokesman for the environmental agency.

Suzanne Burton, of Syracuse, treated her husband, Jim, to a rail bike ride for his birthday, accompanied by their grandchildren, Saige, 8, and Jaiden, 5. “If you give somebody an experience, they’ll remember it more than if you give them a thing,” Ms. Burton said. “So for Jim’s birthday we came with grandkids to give Jim an experience we’ll always remember.”