There's a tract of hilly land above Coromandel Town that the Department of Conservation might want to keep a careful eye on.
It abuts the 60-acre (24ha) property that's home to the wonderfully whimsical Driving Creek Railway - renowned New Zealand potter Barry Brickell's decades-long labour of love.
What began in 1975 as a purely practical endeavour to transport clay dug from the land's hills to Brickell's workshop, soon morphed into a project of ever-increasing scale.
As Paul Swanwick, a former local policeman who now drives the trains, explains, Brickell "found he rather enjoyed the laying of the track and knew he had 60 acres to fill up, so he decided to continue".
Three kilometres of track, three patient bank managers and 28 years later, Brickell reached the boundary of his land.
"He was eyeing these hills above us here, thinking that would be a lovely challenge for the next piece of railway," says Paul, "but of course it's not his property.
"[It's] DoC's in fact ... so he had to be content finishing where he did."
We're standing at the top of the Eyefull Tower which marks that terminus.
Completed in 2002, it offers panoramic views across the regenerating bush below and out to the Hauraki Gulf in the distance.
I'd visited Driving Creek once before - half my life ago - but had been eager to return with my husband and our young son Bryn, who at 16 months was really starting to embrace any mode of transport with an engine component.
Piling on to our train Linx half an hour earlier, he'd been momentarily startled by Paul's first blast on the horn but by the time we'd chugged our way to the halfway point at a wee station called Hoki Mai, he was grinning from ear-to-ear every time there was a toot.
One of the railway's five trains snakes its way through the native Coromandel bush. Photo / Eveline Harvey
As we zig-zagged ever higher, through tunnels, over bridges and around spirals, Bryn found his voice, exclaiming at the trackside trees and sculptures that captured his interest and bouncing up and down on our laps with excitement.
On arrival at the Eyefull Tower, he happily explored the expansive deck as Paul talked the assembled passengers through the area's history and the effects the triple assaults of kauri deforestation, gold mining and farming have had on the landscape over the years.
It's inconceivable now, but from the 1870s until the Great Depression cows were grazed on the same precipitous hill Brickell had designs on.
Then again, perhaps this land lends itself to unusual ventures.
The narrow-gauge railway that now snakes its way past banks reinforced with glass bottles (from all the parties held during construction, of course) and hand-built bridges, is an unexpected marvel amid the rugged bush terrain.
More so, when it becomes apparent just how much hard labour Brickell put into the project.
Despite having no formal engineering qualifications, he built all the bridges and bent all the rails himself using a jim crow.
To determine the best route for the railway, an "old theodolite" was employed, says Paul.
Not content simply with building a classic Kiwi curiosity, Brickell - and now his 13 staff - have also made a huge contribution towards restoring the land by planting more than 27,000 native trees on site - including 9000 kauri seedlings.
Bryn Harvey is all smiles after a trip on the Driving Creek Railway. Photo / Eveline Harvey
But perhaps the most remarkable part of this railway's story is that it was never intended as a tourist attraction at all.
It was just one man's burgeoning hobby - added to as time permitted when he wasn't busy cementing his reputation as a studio potter.
Indeed, it was only opened to the public in 1990 at the behest of the local bank manager, who suggested to Brickell that charging people a fee to ride his railway might be a good way to ensure his mortgage would eventually be paid off.
The tactic worked, but not before enough was borrowed to extend the track to the boundary.
Brickell, who's now in his late-70s, still lives on the property but doesn't have much to do with the railway anymore, Paul says.
That may be the case, but with such a history of enthusiastic development, a small part of me would be entirely unsurprised if I find the track extended even further up that hill next time I visit.
Getting there: Driving Creek Railway and Potteries is at 380 Driving Creek Road on the outskirts of Coromandel Town. It's not quite three hours' drive from Auckland, via Thames, or you can take the 360 Discovery ferry from downtown Auckland to Coromandel Town and catch a Coromandel Adventures shuttle to Driving Creek.
Riding the rails: The one-hour return train trip runs twice a day year-round and six times a day over the summer. Book at least a day in advance to avoid disappointment.
Eveline Harvey was hosted by Driving Creek Railway and Potteries and assisted by Destination Coromandel.