As the crow flies, the twin communities of Seton Portage and Shalalth in B.C.'s southern Interior aren't particularly remote. But birds can travel over a straight trajectory. For humans, the trip is much more painstaking.

One route takes you beside Anderson Lake, up and down a white-knuckle gravel road that clings to cliffs high above the water. The other takes you up and over a mountain pass, an hour-long journey of hairpin turns from Lillooet.

Until 2002, BC Rail ran a passenger service from North Vancouver that snaked through the Coast Mountains to Seton and Shalalth, onwards to Lillooet and further north to the city of Prince George.

When passenger service was cut, the Tsal'alh First Nation was given a reprieve because rail service was deemed essential for the community. The Kaoham Shuttle was born — now run by CN — trundling the roughly 22 kilometres from Seton to Shalalth to Lillooet and back again.

Wild apple trees envelope an abandoned church in Seton Portage. (Matthew McFarlane/CBC)

The rail line is as unique and quirky as the histories of the twin communities it serves.

The land around Seton Portage is actually a massive landslide that came crashing down the mountain some 10,000 years ago. It cut a single lake into two: the upper Anderson Lake and the lower Seton Lake.

It's a community with a micro-climate — residents claim it's the hottest place in Canada — and also a place that has seen boom after bust after boom.

A train shuttle serving residents of tiny Shalalth and Seton Portage in B.C.'s southern Interior has become less reliable, but remains a popular tourist attraction (CBC)

Seton Portage turned into a busy place once the Cariboo Gold Rush kicked into high gear in the early 1860s. Boats sailed up Anderson Lake, stopping to pick up people and gear as they hightailed it over the three-kilometre portage to Seton Lake and onward north.

So many people passed through that Seton Lake became the site of B.C.'s first railroad, the Pacific Great Eastern Railway, later named BC Rail. Soon, Europeans arrived, planting orchards. During the Second World War, it was the site of a Japanese internment camp. And BC Hydro created its Bridge River complex, a series of nearby dams that provide about eight per cent of the province's power today.

Seton Portage lies between Anderson Lake (pictured) and Seton Lake. (Matthew McFarlane/CBC)

The one constant amidst the change was passenger rail service. But now there's a fear that the Kaoham Shuttle is living on a knife's edge. Ever since CN Railway took over BC Rail, the shuttle has become less reliable, said William Alexander, a councillor with the Tsal'alh First Nation.

"The shuttle agreement is that there would always be a train, except on Christmas Day," Alexander said. "CN has been really hard to deal with. They don't talk to us very much."

And that unreliability has the community worried for its future. There's just one conductor left, and service has been cut back to eight days on, four days off as a result.

The Koaham Shuttle gets set to leave Seton Portage on its daily trip to Lillooet. (Matthew McFarlane/CBC)

The Tsal'alh government has proposed new conductors, but the band says CN hasn't responded.

The community's elders are the hardest hit by the lack of a consistent schedule. Vanessa Blake, who works as the town's librarian drives people to appointments outside town when the train doesn't run.

"If the shuttle's not running they have no way of getting out of town to doctor's appointments or whatever. There was an elder that I drove to several doctor's appointments because he couldn't get out. So I would take time off work."

CN, for its part issued a statement, saying it "understands the importance of this shuttle for the community." It suggested it will meet with community leaders to look for solutions, something the band says it's eager to see happen.

The irony of the situation is that despite its uncertainty, the Kaoham Shuttle is a big tourist draw. The BBC described it as "Canada's greatest hidden rail trip." And every voyage is packed with tourists trying to take it to Seton Portage.

A brand new hotel was recently completed in Seton, drawing more and more tourists to the idyllic valley, to take in the two lakes, the forest, the waterfalls. For locals, they hope that trip continues to begin and end on the Kaoham Shuttle.