Sophie Campbell rides the new Welsh Highland Railway on a restored engine bound for former glory.
Sarah and Alex Bell are holding hands over a train table. "I liked trains but I was far more interested in Alex," Sarah recalls, as her husband of two years looks suitably bashful. "It was only when we were overlooking the track, with a Garratt engine coming towards us, that the power and glory of steam suddenly converted me. We married a year and a day later."
Blimey. What is it about steam trains? What on earth is a Garratt engine? And why do I think I'm about to find out? Sarah and Alex are sitting in the first carriage of a train on the newest railway in Wales, where the only thing that stops them gazing at each other is the sight of something really sexy: a newly restored engine or a particularly well-laid set of rails. Not to mention a front window full of rural Wales, passing in a glorious blur of bluebells, spring woods and sheep Velcroed to the green skirts of Snowdon.
At the rear of the train, in first class, where there are free-standing armchairs and the observation car has a single pane of glass carefully curved to avoid unwanted reflections, are the gold sponsors: people who have given £6000 ($12,290) or more to make this day happen.
In between are 150 silvers (donors of £200 or more) and volunteers who have given not only money but days, weeks, sometimes years of their lives to shovel coal, lay track and lug sleepers. They are all bonkers, obviously. I don't think I've ever been on a happier train ride.
The new Welsh Highland Railway, which runs down the western edge of Snowdonia National Park in north-west Wales, has been creeping towards this moment for the past 12 years. It went south from Caernarfon to Dinas in 1997, Waunfawr in 2000 and Rhyd Ddu in 2003.
Now it is open as far as Hafod y Llyn and later this year the missing link into Porthmadog should be complete. Not only will train buffs and tourists be able to transfer to its sister route the 22-kilometre Ffestiniog Railway from Porthmadog up into slate country at Blaenau Ffestiniog it will also open up Snowdonia to cyclists, walkers and those without a car.
As we pull out of Waunfawr and start climbing, there are exclamations of pleasure. Not just at the scenery, as the great mountain rears up above us with its broad summit lost in the clouds, but because nobody can quite believe it's happening.
The leaders of the track gangs groups of volunteers who laid the steel rails and sleepers josh each other over who holds the top-speed record of 800 metres in 2½ days.
"There's Roland's Runner!" the cry goes up as we pass a contraption invented by a volunteer to move rails. Everyone winces as we scrape against granite rubble dumped too close to the rails: they're worried about Gary, who painted the livery and crests and tricked out the interiors in cream and coral.
The Welsh Highland Railway has cost £28 million so far and needs a further £300,000 to reach Porthmadog. The five engines were shipped from Africa and Tasmania for restoration. All the carriages, bar two originals, have been made from scratch by full-timers and volunteers at the engineering works at Boston Lodge. It's smart, comfortable and deliberately designed to be a different experience to the Ffestiniog, with its Victorian heritage carriages.
"These were always private railways, they were never nationalised," explains one of the supervising engineers, Stuart McNair.
The Ffestiniog opened in 1836. Slate had left the mountain on donkeys but the new narrow rails could cope with the terrain. Carriages were horse-drawn until it became the first narrow-gauge railway in the world to use steam. "There was a massive slate boom in the 1860s and '70s," McNair says. "The North Wales slate barons became some of the richest people in the country that's when they built castles like Penrhyn." The poor old Welsh Highland Railway, completed in the '20s, missed the boom and limped along for 17 years before closing. Fortunately for preservationists, neither railway disappeared.
The Welsh Highland Railway, too costly to remove, gradually gave way to walking and cycling paths and people's gardens. The Ffestiniog could not be demolished without legislation, so it was mothballed. According to the general manager of both railways, Paul Lewin: "They flung open the doors to Boston Lodge and all the engines were still sitting there, untouched."
Lewin is sitting one carriage up from first class, chewing the fat with engineers, volunteers and board members. His father built miniature steam railways for amusement parks. "I've got pictures of me aged five, going around and around in circles," he says. "You ran them in, like cars."
All day I hear similar stories: people whose fathers worked on trains; people whose families holidayed in north Wales and went on the Ffestiniog for a treat. Women account for about half the 7600 members and management team.
Outside, we reach the high point of the railway at Pitts Head, 200 metres above sea level. It's steep, a one-in-40 gradient a mainline track would rarely be more than one in 100 with sinuous S-bends. That means it can't be used in winter; even spring is tough on the engine. But we're over the hill and running for the Aberglaslyn Pass, the first time any passengers have travelled this far, with attention turning to the landscape. We follow the pretty Glaslyn River down to the Porthmadog flood plain through mixed woodlands. Hills and escarpments erupt to the south. Meadows nod with ladies' smocks and buttercups.
We pass the village of Rhyd Ddu, one of several places where hikers can leap out and make for the summit of Snowdon and Beddgelert Forest campsite, one of the biggest in Wales and an important market for the train.
Gelert was the hound of Prince Llewellyn and Beddgelert is as famous as the site of his grave; a corking story made up by the landlord of the Royal Goat Hotel to drum up custom.
As we pass an osprey's nest belonging to Wales's first breeding pair all paths nearby close during the breeding season, so the train is a useful vantage point the day is coming to an end. Or it is for the triumphant passengers, who have just seen a dream come true.
I, on the other hand, am going to make a mad dash to catch the last train of the day on the Ffestiniog Railway. The steam, the soot, the Garratt engine ... Really, I could get into this.
For information on the Welsh Highland Railway and the Ffestiniog Railway, see festrail.co.uk. The Welsh Highland Railway will operate to the end of October: single third-class tickets £6.60-£17.50, depending on stops; returns £9.90-£25. First-class upgrades from £5 one way. Dogs and bikes £2.50 one way.