I STARE into the darkness through the train window. Glens and Bens may fly by, but I wouldn’t know.

Eventually, the morning light reveals a dreich Friday morning. Despite this, my mind bubbles with excitement as I hurtle south.

Destination: Forth Bridge.

For the past year, I have held the ­position of writer-in-residence, promoting the ­iconic ­structure in words, both here and afar. The best part of it has been to discover what goes on behind the scenes of Scotland’s famous icon – some of the ­stories people have told me, some of the drama and adventures!

When I mention this to my publishers, they seem interested. What stories? What secrets?

One of the first people I meet is Colin Hardie. As a writer, my bread and butter is to imagine walking in other people’s shoes for a while. Well, what about the steel-capped boots of this former bricklayer?

My first impression of the man is steel. As senior construction superintendent for Balfour Beatty, the buck stops with him. Clad in high-visibility overalls, the 60-year-old removes his hard hat and ushers me towards a cabin beneath the Forth Bridge where it will be quiet enough for an interview. Shadows of the bridge’s many tubes and lattices criss-cross our path.

Back in 2001, the Forth Bridge was due for major ­refurbishments. “The rail bridge needs someone with temporary works experience,” a colleague suggested to him. “Nah, that’s no’ really me – I’m a builder!” he retorted, before relenting: “OK I’ll come for six months.”

Almost 22 years later, he is still here. He recalls his early days as a foreman.

“The first thing that strikes you is the size – even then, I remember thinking this is enormous. I was used to working on ice rinks, ­shopping centres, football stadiums, you know, big things, but this was something else. And it wasn’t just the bridge itself – I couldn’t believe the size of the temporary works – and we were building them from the top down!

Up to then, I had only built scaffolds from the ground up. It was a whole new technique, the bridge as a support, using ropes. All of that was new to me.

“During the refurbishments, the place was like a small village, with 400 or so workers for the best part of a decade. We had hoists to the top, and ­barges ­below. Doing the work from a boat was new to me too. They say every day is a learning day. It really was.”

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I am struck by the respect for the Forth Bridge in his voice. He reflects: “Truth is, I wouldn’t be here for as long as I have if I didn’t love it. There’s not another bridge in the world that’s like this. I’m not soppy about it, but It’s a fantastic place to work. You won’t get better, you genuinely won’t.

“Don’t get me wrong, it’s hard. In the summer you get the heat belting off the steel; in the winter you get -14 degrees with the wind chill. But it’s ­rewarding – and not just financially. You’re ­contributing to something.”

I begin to list others who may have light to shed on unexpected secrets of the Forth Bridge. Who are the people on, ­under and around the bridge with stories to tell?

The more I look, the wider the reach of the Forth Bridge stretches, and I have an epiphany of sorts – the Forth Bridge is a metaphor, too. It spans more than a body of water – it spans centuries, communities, land and sea, past and present.

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Just like the six-and-a-half million ­rivets holding it together, there are countless points of contact between the people and places all around the bridge. ­Engineers and environmentalists, managers and mental health activists, construction workers cleaners and campaigners.

Some rub up against each other, others pass each other by – but ultimately, it is the only thing which unites them – and they claim it as their own. Somewhat cheekily, we settle on Made from Girders – Our Forth Bridge, as the title.

Now the interviews start in earnest. Train driver Gavin Black grew up in South Queensferry and often bought chips by the Hawes Pier during school lunchtimes.

He discovered a profitable pastime: “In the ferns by the steep steps behind the Hawes Inn, right beneath the access track under the viaduct, I found a broken rivet from the bridge. It still had a bit of the orange paint on it. I sold it to an American tourist for a tenner – that was a lot of money to a boy in the eighties. I never told my pals though, otherwise they might have tried to look for rivets too. Over the years, I found three more, selling them all to tourists. I regret that now, but if you are a kid, all you can see is the money.”

Now he drives trains across the Forth Bridge up to 30 times a week.

“Driving a train across and travelling as a passenger are completely different things. As a passenger, you can only see where you are. As a driver, you can see where you are going. You see how the structure expands in summer and you see that it’s far from straight – it zigzags around everywhere.

“And you are so close to the edge, ­especially on the viaducts; there is a ­proper sense of height. You’d think it would open up as you go on to the bridge. It actually closes in as you enter the ­structure.

“I remember the first time I drove onto the bridge in a high-speed train, early in the morning, in this massive locomotive. When you’re coming onto the structure at 50 miles per hour, the ground around you just falls away. All of a sudden, you’re 150 feet in the air! It’s a thrill.

“There are five million people in ­Scotland, but I am one of very few who are lucky enough to see this.”

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Not everyone I speak to is physically on the bridge. One local community activist bobs in the water beneath, for example. Gina Bees is a breath of fresh air – curly-haired, smiley-faced, bespectacled and congenial. I warm to her immediately.

“What do we do? Well, we basically throw ourselves into the freezing Forth, all year round!”

She explains the benefits of running a regular mental health swim in the Forth Bridge’s shadow.

“We all live in our heads too much, don’t we, with our busy lives? Well, when you swim, for the first minute or so your mind empties entirely – all you can think of is how cold it is, how it stings. And then you slowly reconnect with your own body and that zingy feeling begins – and you realise that you can do hard things.

“Bobbing around in the bracing water helps regain perspective on whatever else is going on in life.

“Even the Forth Bridge looks different from the water. It’s always stunning of course, but in some ways, it’s an anchor too. You know exactly where you are, and that’s reassuring.”

As Forth Bridges area tourism strategist, Karen Stewart promotes the bridges to visitors.

She laughs: “A lot of my time is spent on social media.

“There is so much photography ­content out there, and it keeps me on my toes. The top performers in terms of ­content engagement are definitely aerial ­photos – you know, when people fly into ­Edinburgh Airport and snap the three bridges from the window? Those pictures do really well!”

Those volunteering in local heritage groups are rich mines of information. Garry Irvine of North Queensferry tells me of meeting an old lady.

“She had lived right under the bridge, or maybe one of her relatives had. ­Anyway, she told me that they were out in the ­garden and found a man’s head. You see, trains were passing over the house all the time, and in those days, you could still open the train windows. This man had literally lost his head looking out the ­window. True story.”

Len Saunders of South Queensferry has more stories: “There is an urban myth of two workers being trapped in the ­caissons, after accidentally being ­concreted in.

“The legend alleges that the pair of trapped workers were supplied with poisoned food to hasten their deaths and ease their passing. There is no evidence that this actually happened.”

Perhaps the most dramatic incident I came across relates to an unassuming man called Donald Scott.

He recalls: “It was an April morning. When you are working on the bridge, you don’t say that you’re feeling dizzy. You’re going nowhere if you say that. I was ­feeling dizzy that day, but I said nothing. But when I popped out of the wee ­lunchroom at track level because I needed some air, I just collapsed.”

Donald had suffered a cardiac arrest on the Forth Bridge.

He had taken a job as a sheeter ­during the Forth Bridge refurbishment – at ­almost 60 years old. The job took him to the structure’s most precarious locations.

“Teams of eight to 10 men had to ­manually take rolls of thick plastic ­sheeting up the bridge from track level – no hoist was big enough for these loads. They then attached the sheeting to the outside of the scaffolding to allow the refurbishment work to get underway. It was windy, like,” he states simply.

“The scariest thing was swinging round to the outside. Some guys couldn’t do it. I took my turn though. Thank God I wasn’t doing that on the day I took ­unwell. I’d be gone.”

I wasn’t there when Donald Scott was lowered to the safety boat by crane and rushed to shore where, by an ­extraordinary turn of good fortune, two paramedics were having coffee nearby and hurried to help.

Nor have I personally witnessed the many stories of RNLI rescues, tourist trip-ups, celebrity stunts and dramatic discoveries. But in words and pictures, photographer Alan McCredie and I have become custodians of these stories.

As I complete my year as ­writer-in-residence, I can think of no greater honour.