I love rolling through the tightly folded steep-sided hills and starkly contrasting curvaceous hummocks, created by lahars, of the King Country. Wedged between Waikato and the Taranaki, I recently ventured this eye-catching pocket of our heartland to sample the much buzzed about offerings of Forgotten World Adventures.

Based in Taumarunui, this incredibly enterprising tourism venture boasts a compelling platter of soft adventure excursions, prising open the stories, legends and unspoilt scenery of the hinterland. Taumarunui’s official slogan is “Where Adventure Begins” – a catchy little tourism tagline that successfully embodies the essence of Taumarunui’s visitor pull.

My adventures began with the tumultuous April weather, which threatened to sabotage my best-laid plans to plunge into the Forgotten World. Mercifully, the weather gods calmed their farm and my first assignment was to sample riding the rails of the old and decommissioned line connecting the King Country with Stratford. Taking 32 years to build, the Stratford – Okahukura Line (SOL) finally opened in 1932. The line had been commissioned to transport products from the emerging farming, coal and logging industries.

Forgotten World Adventures have re-opened 142 kilometres of this retired line, including 24 tunnels and 92 bridges. You’d be hard pressed to find a more scenic decommissioned railway line. The pioneering founder of Forgotten World Adventures, Ian Balme, was a Waikato farmer who dared to dream big, turning a mothballed rusting eyesore into a visionary business. Since 2012, his staff has ballooned from 3 to 38 after secured a 30-year lease with KiwiRail to operate semi-guided tours along the line between Okahukura and Stratford.

I joined the daily 5 Tunnel RailCart Tour, which is a four hour return romp along the abandoned railway line. I was struck by the mounds of pumice and mud that had been painstakingly dug off the tracks, after ploughing down hillsides in the recent rainstorms. Half the railcarts had been buried in pumice. Our guide remarked that the prohibitive costs of constant track maintenance underpinned KiwiRail’s decision to pull the plug on the line’s operation in 2010.

At the obligatory safety briefing, we were given a beginner’s guide on how to “drive” the railcarts. This is certainly no train ride, but a unique self-drive rail journey in converted golf carts. Petrol powered and limited to a top speed of 22km an hour, these souped up golf carts originate from Arizona, but given the lush and vivid greenness of the surrounding landscape, they certainly don’t look out of place. A dozen fellow cart riders comprised our convoy, which was led by a guide, who kept an eagle eye out for any debris on the track.

The commercial glory of the Forgotten World region may have long faded but the wrap-around scenery is deliriously good. Volcanoes press at its either side, state highways swirl around it, but the heart of the Forgotten World is a bucolic, and at times, rustic symphony. Animals vastly outnumber people in these parts, as we tootled by goats, deer, alpacas and happy herds of cows on elevated pastures, surrounded by superlative views.  In quintessential New Zealand style, a vast flock of sheep were being shifted along the nearby road, dutifully under the guard of crowd-wrangling sheepdogs.

 Clattering along the tracks in our carts, curling through valleys and creased hills, we traversed lichen covered bridges spanning rivers, while more lichen streamed down from trees like confetti. The verdant countryside is sprinkled with clutches of ramshackle houses and dilapidated farm buildings, strutting the skyline as reminders of the region’s boom times, when primary industries like timber-milling and coal-mining thrived. It’s sobering to reflect on the dramatic population changes in some of these settlements.  When the railway opened, Tangarakau had a bustling population of 1200. At last count, this ghost town now has just 8 residents.

We stopped for scrumptious home-made snacks and a hot cuppa in the sleepy village of Matiere. It’s still home to around 40 residents – and housing is dirt cheap.  A rating valuation of $15,000 is not uncommon. A couple live in the former Catholic Church, which they bought for $1100. At its peak, 80 years ago, Matiere had a population of 750, built on saw-milling and farmers breaking in land. Information posts along the route, complete with historical photographs, illustrate how bustling many of these lineside communities used to be.

But the undeniable highlight of riding these storied rails are the tunnels. As the name would suggest, my 5 Tunnel Tour traversed 5 of the 24 tunnels on the railway line, including the only brick-lined tunnels laid by hand and the longest tunnel on the line, spanning 1500 metres. Apparently it comprises 3.5 million bricks! Boring through these tunnels and admiring their damp, jet black walls, illuminated by the headlights on our carts was absolutely thrilling. It certainly pays to wrap up warm. They can be bone-chillingly cold.

The 1500 metre  tunnel, known as the Okahukura Tunnel, is actually New Zealand’s seventh longest rail tunnel, taking ten years to carve. Adding to the ethereal theatre, a thick mist draped the middle of the tunnel as we tootled through it, before re-emerging from the darkness into spectacularly sunlit native bush and farmland. Rail travel has always exuded a romanticism. The supreme sense of scenic intimacy is not matched by road travel and the novelty of piloting your own passage along the tracks is an undeniable winner with the Kiwi love affair with anything DIY.

Forgotten World Adventures offers a variety of touring options. The 20 Tunnel Tour is a 10 hour affair reaching Whangamomona. “The Ultimate” is a two day tour spanning the full 142km length of the line, all the way to Stratford, after sleeping overnight in Whangamomona.  In addition to the railcarts, you can also try your hand at the New Zealand-made RailBikes, with side by side seating, on the 5 Tunnel and 10 Tunnel tours. Only a moderate level of fitness is needed.

I also took a ride on the Forgotten World Jet for a flavour of the beauty, reverence and heritage of the Whanganui River. My driver/guide was Robert Carter, a local legend who has been guiding visitors along the river for 35 years. He pointed out to me the astonishing amount of volcanic material, discharged by Taupo and Ruapehu, that has stamped its presence on the landscape..     

Forgotten World’s new custom built 15-seater jetboat operates various excursions including a 232km return journey to the Bridge to Nowhere, and on the multi-day excursions, she’ll zip you all the way down to Whanganui city. In fact, Forgotten World Adventures operate the longest commercial jetboat rides in the Southern Hemisphere.

If you’re taking an overnight excursion, be sure to spend a night in the self-proclaimed Republic of Whangamomona and get your passport stamped at the Whangamomona Hotel. It’s truly one of New Zealand’s legendary watering holes. While in Taumarunui, my head hit the pillow at the Forgotten World Motel (formerly known as the Hilton.) My well-appointed unit was clean, quiet and toasty, the beds are cloud-comfortable and there’s free Wi-Fi. For further details on the full product range, head to www.fwa.co.nz

Mike Yardley is our Travel Correspondent on Jack Tame Saturday Mornings.