IT IS as you cling precariously to the side of the mountain and see a rickety bridge straight out of the Road Runner cartoons that you expect Wile E Coyote to leap out and stop you in your tracks.

But just before the train trundles out onto the shaky structure, the rails robustly lead you off in another direction. That clearly was a bridge too far on the Gold Rush railroad into the wilderness.

We’re riding the White Pass & Yukon Route out of Alaska and across the border into Canada – and adventure awaits, quite literally, around every twist and turn of the tortuous track.

Travelling in vintage carriages with small balconies on which you can step out to take photos, it’s like stepping into the past. We’re pulled by a diesel train, but there are steam runs too.

From sea level Skagway we climb steadily ever higher to the 2,885ft White Pass summit, passing over evocatively named landmarks like Black Cross Rock and Dead Horse Gulch.

The former was where a blasting accident on August 3, 1898, buried two railroad workers under a 100-ton granite boulder, and the black cross still keeps vigil over their tragic final resting place.

Ditto Dead Horse Gulch, where 3,000 pack animals met their end during the great stampede that same year. Life up here was tough back in the Gold Rush days. Still is, especially in winter weather.

It took tens of thousands of men, and more than 450 tons of explosives, to cut the White Pass narrow gauge rail tracks into solid rock, through mountains and over steeply sloped gorges.

At least 35 men lost their lives before the railway finally reached the White Pass summit in 1900 and Fraser, where the border station stands between Alaska in the US and Canada’s British Columbia.

Views on the way up are spectacular. And at Denver, crossing the east fork of the Skagway river, there’s a red caboose cabin that can be rented through the US Forestry Service.

From time to time we stop to take on hikers and trekkers who flag the train down as they emerge from the wilderness trails. The White Pass route operates an ‘on demand’ service.

Make sure you get out on the carriage balcony just before the seven mile mark where Rocky Point offers fantastic vistas down the valley with Mt Harding and the Harding Glacier as backdrop.

There’s graffiti on Buchanan Rock but don’t worry. It dates back to the 1920s and has become a tourist attraction in its own right (or perhaps that should be write).

“On to Alaska with Buchanan,” it reads, painted by the Buchanan Boys Tour Group, youngsters who were brought in from Detroit each year to visit Skagway.

On past the aforementioned Black Cross Rock memorial and you’re rewarded with views of Bridal Veil Falls which cascade 6,000ft from the glaciers at Mt Clifford and Mt Cleveland.

We trundle through the old Henley and Glacier Stations before plunging into the 2,275ft Tunnel Mountain, where the tracks cross a trestle bridge 1,000ft over Glacier Gorge.

Inspiration Point is the next photo favourite, seventeen miles up the mountains from Skagway and offering views of Lynn Canal, Mt Harding and the Chilkat Range.

Onward again, past Dead Horse Gulch, and here, at last, is the bridge to nowhere I mentioned earlier. Once the tallest cantilever bridge in the world, it hasn’t been used since 1969.

It’s here that the track continues instead into a 675ft long tunnel through the mountain, re-emerging into the light by the famous Trail of ’78 – once the main route from Skagway to the goldfields.

At one point we pass an old railroad carriage abandoned in the wilderness. This one is, quite literally, off the beaten track and looks as if someone has lived in it for a while.

The US and Canadian flags fly side by side at the customs station at the White Pass Summit, then we drop down to Lake Bennett and finally to the Gold Rush town of Carcross.

We’re in the Yukon, still 2,159ft above sea level, where we disembark. Yes, that’s me and my wife Sheila in the obligatory photo! Rail tracks run along the main street and across a photogenic river bridge with Whitehorse forty miles distant.

Carcross is just like you’d imagine a frontier town to look like, although that’s partly due to canny traders who play the gold rush card with a tourist trap that boasts husky pups, sled rides and souvenir shopping sprees.

But head down to the river for the chance to photograph the bridge and take time out to reflect on the history of the region and man’s hunger for gold that brought 100,000 prospectors up here.

Gold was discovered in the Klondike by local miner George Carmack and two First Nations companions, Skookum Jim and Dawson Charlie, in Bonanza Creek on August 16, 1896.

When news got out, it sparked a stampede to get rich quick. But it was a gruelling trek up through the mountains. Today, of course, you can let the train take the strain for endless photo opportunities high up in the clouds.

Canadian authorities required each prospector to bring a year’s supply of food in order to prevent starvation, and a Klondiker’s equipment weighed close to a ton.

What with the heavy hauling, and contending with the mountainous terrain and cold climate, many of those who persisted didn’t arrive until the summer of 1898, by which time they’d left it too late.

The White Pass & Yukon Route Railway – “The Scenic Railway of the World” – was built in 1898 and is an International Historic Civil Engineering Landmark, a designation shared with the Panama Canal, the Eiffel Tower and the Statue of Liberty.

It was literally blasted through the mountains in 26 months at a cost of $10 million, and runs for 110 miles – along which way it climbs almost 3,000 feet in just 20 miles – with steep grades of up to 3.9%.

Oh, and several cliff-hanging turns of 16 degrees.

Many thought it was impossible but Michael J. Heney, an experienced railroad contractor, begged to differ. “Give me enough dynamite and snoose” he bragged, “and I’ll build a railroad to Hell.”

The freezing conditions during construction may have made it seem a tad too close to that for comfort but these days, for the tourism trade, it’s closer to the highway to heaven.

For timetables and fares, make tracks to www.wpyr.com. All images my own, taken in 2017, other than aerial shots courtesy of the White Pass & Yukon Route Railway.