Nine o'clock on a June evening, the sun only thinking about setting, and there's a warm wind sighing through the Ponderosa pines. The young woman who served dinner comes by my outdoor table and asks if I'd like another glass of wine. Is that an Australian accent I hear?

Her name is Lee and she's from WA. With her husband Adam, also an Aussie, and their three-year-old son, they're spending a second northern summer working at Kumsheen Rafting Resort in the dry, rugged interior of British Columbia near Lytton, about 300 km. east of Vancouver. "We just love this place," she tells me. "We had to come back – it's like a second family here."

Adam is a guide, that is to say a boatman, running the dramatic rapids on the Thompson River. They're part of a staff of 60, including 22 local Native Indians, working at the resort from its opening in May until its closing at the end of September, a month before the snow begins to fly.

"I had to come back too," I reply. "I did this trip in 1979 and wanted to try it again."

"Ahh... I wasn't born then."

From my spot on the terrace I look down across a pine-dotted meadow, past a row of cabin-tents and a cluster of teepees to the edge of the canyon. On the far side of the river, a 300-metre high, almost vertical granite wall is washed in pinks and ochres by the evening sun. A distant train whistle echoes mournfully. Canada's two transcontinental railways use the narrow canyon to get through this part of BC's mountainous interior – there was no other way to get to the Pacific Ocean.

***

Most visitors to British Columbia, Canada's most westerly province, are aware of the railways because of the famous Rocky Mountaineer which travels from Vancouver up the Fraser River, then along the Thompson directly below the Kumsheen Resort on its way to the Rockies. You can hear trains, mostly mile-long freights, running along the river's edge, and I was looking forward to trainspotting from the raft.

Kumsheen was the name of the Indian village that stood at the confluence of the Thompson with the Fraser, BC's longest and biggest river, in the era before contact and settlement. The rafting company celebrated its 35th anniversary in 2008. Founder Bernie Fandrich was an out-of-work college teacher when he decided to run the Thompson rapids with two friends in an inflatable dinghy that he moved around on top of his Kombi van. Surviving his first trip, he put a sign up on the roadside and soon made a thousand dollars taking tourists out onto the river. He "went commercial" in 1978.

The trip I took in '79 was in August, well after the spring flood but still with enough water in the river to create deep whirlpools and wild, bucking rapids. This time the river would be nearing its high-water mark. Although there was still a big snowpack in the watershed to the east which would add to the torrent as the summer heat intensified, the river was already running fast and grey-green with debris and silt coming down with the snowmelt.

There had been several days in the high-20s which had raised the river's volume to an astonishing 2,500 cubic metres a second, about triple its August level. As I finished my wine I tried to imagine the total volume in all the rivers of drought-stricken Australia. This was going to be a fast trip.

After a tranquil overnight, interrupted only by a few train whistles, and a delicious buffet breakfast, six of us boarded a huge Yukon SUV towing a trailer with our raft. Our two guides, Charles and Ben, drove us about 40 kilometres upstream to the village of Spences Bridge, where the river runs through a comparatively wide valley. It's arid country, a kind of chaparral of sagebrush and bunchgrass dotting the lower slopes of the mountains, with pine forests above, snowy and cold in winter but hot and dry in the summer.

It was a flawless clear morning promising a high of about 30. At a backwater, Charles and Ben launched the raft while we struggled into bright yellow raingear and secured our vermilion lifejackets. "You'll be easy to spot if you go overboard," quipped Ben, our boatman, a muscular young man wearing nothing but shorts and a lifejacket – a bonus for the young women on the raft.

While Charles got the outboard motor running and pulled the trailer away from the shore, Ben manoevered us on board and ran us through the safety drill. The raft was a "J-rig" – two J-shaped pontoons with a wooden deck in between. We sat on the pontoons facing inwards and were told to pay attention to a rope running the length of them at about calf height.

"When we go into the rapids," Ben coached us, "you've got to hold the rope with both hands between your legs. Don't hold on outside your legs because you can get pitched over backwards and dislocate your shoulders! Makes it harder to swim then ..." He gave advice on what to do if we did fall off, including how to assume "a defensive position" to run the rapids and survive crunches with rocks: on your back, feet first, head up.

The water which lapped up onto the decking was freezing on our feet and would be cold when it sprayed us. Hence the raingear, which you don't need in July or August when the air temperature is often in the high 30s and the river's warmed up a bit.

I remembered from my earlier trip the way the raft bucked like a bronco when it hit a wall of turbulence as big as a bus, and how the people in the bow got the worst soaking and pounding. Accordingly, I staked out a bit of pontoon as close to the stern as possible.

After so much preparation, the first two hours were an easy-going, pleasurable drift in the current. The river was quite wide and the raft floated along silently, sometimes sideways or backwards, without needing the engine for steering. Ben pointed out osprey nests, interesting rock formations and the remains of the old Cariboo Road from the gold rush days of 150 years ago.

And there were many trains to spot: loaded coal "unit trains" of three or four hundred cars heading downhill to the port of Vancouver; multi-coloured freights with endless flatcars stacked two containers high, many with Chinese script on their sides, grinding uphill towards the Continental Divide and onward to eastern Canada and the American Eastern Seaboard.

We put in for lunch at the roadhouse at Nicomen Falls, where a chute of water comes out of a rocky cleft like a huge firehose. Build-your-own fajitas and salads, juice and water. Forget the coffee as there are no bathroom breaks. Then it was back on the raft and into the rapids. Fortunately, nobody had overeaten.

The valley narrowed and the raft plunged into sets of rapids and whirlpools including Witch's Cauldron, the Jaws of Death and Devil's Gorge, to name just a few. Ben the boatman, adopting a wide stance in the stern with one hand on the outboard's long tiller and  the other holding a length of rope to steady himself, lined the raft up and powered through the edges of the whirlpools while dodging the huge, rocky crags midstream.

Down we went, sometimes suddenly dropping two or three metres to disappear in a wall of spray. After each plunge we'd motor over to the eddies along the bank and head back slowly upstream before turning and charging back into the vortex from another angle. "Whoooo-eeeee!!" yelled the young ones, while I just hung on. "Whoo, man, this is fantastic up here!" shouted the young construction worker in the bow. "You sure you don't want to change with me?" 

I shook my head. Once I was like you and soon you will be like me, I thought, remembering a tombstone quotation.

The scenery became utterly breathtaking through the granite-walled White Canyon, where the river again widened and slowed. A few ranches occupied flat benches high up above the water. In the distance, the cobalt-blue, snow-capped peaks of the Coast range came into view. Finally, we arrived at the little community of Lytton where the Thompson joins the wider Fraser River. We motored over to the bank where Charles awaited us with the Yukon and the trailer. It was four pm, right on schedule, six hours since we left the resort.

I had driven up from Vancouver the previous day, wandering along the highway and taking seven hours to cover what would have been three hours worth of serious driving. So you actually could raft the Thompson as a day trip, but it's more pleasant to take your time and stay over. Kumsheen also offers a range of longer trips, including multi-day paddle-raft adventures.

Why do it? As an adventure, power-rafting offers the same sort of thrills as roller-coaster riding – a great day with a group of friendly strangers. But it's also a chance for a reflective personality to imagine river travel in an earlier era. Just like going by train, rafting offers a very different perspective on a piece of landscape than the point-A-to-B typical car trip.