I must admit it is very odd the way our grandchildren divide up. “Can we go up the attic, Grandpa?”, they all say, where they know they will find my much cherished model railway.

But by the time I puff upstairs, the boys are all pressing the buttons and turning the knobs that control the engines, and the girls are on the floor juggling the furniture in the dolls’ house. However hard I try to enthuse my granddaughters about the enchantment of the trains, they stare blankly at me and dive back into the little boxes.

It baffles me that they are so uninterested when model railways are so fascinating. Who wouldn’t want to enjoy spending hours playing controller on your own private line?

Yet I must acknowledge that not everyone is as enthusiastic as myself and my grandsons. Indeed, this week, 53-year-old Simon George, who has just unveiled the biggest model railway in Britain, admitted he had kept quiet about his eight-year labour of love when he met a new girlfriend last year. “Model railways don’t have a great reputation,” George said. “I didn’t want her to leave me in horror.”

George revealed his passion had started in childhood when as a 12-year-old he used to watch the real trains rumble by. From there it was a short trip across the tracks, as it were, to model railways.

My first memories of trains began with the miniatures, not the real things. I still dream about my first loco – a really big, yellow beauty. It only went round in a small circle but I played with it all day. Goodness knows where it is now.

But the passion had been ignited and I was never able to resist admiring a new engine or piece of landscaping, even though during my early working life there was nowhere to lay out a scenario, at least not permanently

So my real break came in the 1970s when we moved into a house, with a top floor bedroom – and bingo! – the stairs came up in the middle. I was able to thread a double train line around the walls, behind the bed head and through the en suite bathroom. It was a delight.

Now we’ve a rambling house in south west London with an even more spacious top floor – perfect for the Eurostar to zip along the outside rail while snakier trains can potter round the sharper corners of the inside lines.

Like most enthusiasts, I am a stickler for details. It was a challenge designing the layout and massaging papier mâché hills and tunnels into shape. Maddeningly I failed to crack a circular junction that would have allowed me to make a train swing around and run back along the same track. I was told it was easy – just solder in some little cut-out switches. But after a day’s work I threw the whole lot up in the air and settled for having to turn the trains around manually.

I did a lot of travelling as a correspondent and made a point of picking up a foreign carriage wherever I went. The only problem with that is that the couplings often vary and I am hopeless at fidgeting with little fittings that need changing.

I’m lost in admiration and envy at the complexity and realism of layouts like George’s, which features scale models of 30 trains running on 1,500m of track to a specific timetable displayed on arrival boards. Rod Stewart, of course, is another aficionado with wonderful detailed layouts. His magnificent skyscrapers and elaborate bridges reflect the buildings of New York and Chicago 80 years ago.

I’m much less excited by the surroundings: for me nothing can beat the delight of placing my eye at track level and watching the trains rattle towards me. The vision is best when the approaching locomotive is followed by a variety of wagons and trucks loaded up by the kids with piles of bits and pieces from the dolls’ house that weigh the wagons down and stop them falling off the line.

It is hard to explain this obsession, as hard as it is to understand why men are more inclined than women to throw themselves into all this. But for me it’s like sitting in a gallery in front of a fine painting or lying back in an armchair lost in the sound of a Beethoven symphony. Gazing at the comings and goings of the trains and their cargoes is a refreshing source of relaxation and escape.

When I was caught up in the magic of inventing graphic ways of illustrating election results some of the best ideas flashed across my mind up in our attic: one of the best images was the one-time Tory leader William Hague on a rollercoaster that represented his up and downs in the opinion polls. It came to me in an inspired moment with my model Pendolino racing along under the rafters.

It remains a mystery to me why my wife Ann and all the women in the family have no interest at all in the miniature funfair at the top of the house. They’re missing a whole world of joy.

Treasures of World History – 50 Documents that illustrate the Story of Civilisation by Peter Snow and Ann MacMillan. To order from Telegraph Books, call 0844 871 1515 or visit books.telegraph.co.uk