There are few love affairs more passionate than that of the British with their trains. On a basic level it's obvious. We invented the railways, and pride in the great heroes of the railway age – the Stephensons, Trevithick, Brunel – runs through our DNA.

But like all the best love affairs it's a more complex and contradictory relationship than this – which is why we all get very worked up about the RMT leader Bob Crow and why we all heaved such a sigh of relief that he's had his comeuppance in his attempt to call a national rail strike, if only for the time being.

In fact, statistically, relatively few of us travel on the railways at all – a tiny 8 per cent of all journeys in Britain are by train, and seven in 10 of all rail journeys begin or end in London. Yet the railways have a disproportionate grip on the national psyche. We grumble about high fares on trains we never travel on, and poor fare in buffet cars we have never patronised. Leaves on the line, the "wrong kind of snow", the curling railway sandwich – all are the stuff of legend. A national newspaper editor recently told me that a knocking story about the railways on his front page could add 20,000 to the circulation.

But beware of overstepping the mark. Deep in the British soul the railways represent an idyll that we challenge at our peril, even if we never travel by train. It's the innocent world of Thomas the Tank Engine, Oh, Mr Porter!, The Titfield Thunderbolt and The Railway Children (the film of which has just been given a 40th-anniversary re-release).

In our mind's eye we see that country branch line with wheezing old engine, milk churns on the platform and the porter's cat slumbering on the station seat. As the distinguished railway writer Hamilton Ellis once put it: "Surely it was always summer when we took our first rail journey!" Brother Bob has acquired the status of national bogeyman precisely because we care so very deeply.

Like the best love affairs, here is an attachment that defies explanation. "The curious but intense pleasure that is given to many by railway trains is both an art and a mystery," wrote the historian Roger Lloyd. "It is an art because the pleasure to be had is exactly proportionate to the enthusiasm one puts into it. It is a mystery because it is impossible to explain to others. The connection between the sight of a railway engine and a deep feeling of satisfaction is very real for multitudes of people, but it eludes rational analysis."

What is certain is that the fascination appears to develop at a young age and pass through the generations. How else do you account for children who have never been on a train – let alone their parents – still thrilling in vast numbers to the implausible adventures of some quaint old steam engines with funny faces, written by a fusty provincial clergyman in the 1940 and 50s?

There's not just collective nostalgia at work here. Last weekend I took my eight-year-old son to the Festival of Model Railways at London's Alexandra Palace. It was not full of sad stereotypical men with anoraks and vacuum flasks, wearing enamel badges and sporting peculiar haircuts. Here were thousands of ordinary families clearly having a great day out to celebrate what is still reckoned to be Britain's biggest indoor hobby.

This Easter weekend, it will be the same all over the country, with families young and old turning out to visit one of Britain's 100-plus preserved railways which play a big part in the British leisure industry, carrying six million passengers a year, employing 20,000 staff and volunteers, and with a total mileage bigger than the London Underground system.

Others will be standing at the lineside to watch a mainline steam express train pass by. (Though it is fashionable to moan about rail privatisation, its "open access" rules permit the running of historic "giants of steam "on the main lines in the 21st century.)

Not long ago I travelled on a record-breaking London to Edinburgh run with Jeremy Clarkson at the regulator of Britain's newest mainline steam locomotive Tornado, built by a group of enthusiasts who had clubbed together to raise £3m to build it. Not only did thousands of ordinary folk line the tracks to wave Tornado on its way (many of whom would probably re-inhabit their alter egos as angry commuters the following morning), but Britain's most famous petrolhead became a true convert.

Now the strike threat is lifted, others may choose to explore the national network on lines that offer some of the greatest journeys on the planet. I've spent the past year travelling on some of these country railways in the remotest parts of Britain for a new book to mark the approaching 50th anniversary of the Beeching report. Even today Richard Beeching, infamous chairman of British Railways in the 1960s, stands, like Bob Crow, high in the national pantheon of evil. (He was recently cited by Quentin Letts in his book 50 People Who Buggered Up Britain.)

Thankfully, many of the lines targeted for Beeching's famous axe were reprieved through the efforts of dogged local campaigners. So today we still can travel past the magical lochs, mountains and valleys of Scotland's West Highland line, recently voted the most scenic in the world. Or at the other end of Britain take the slow train from St Erth to St Ives in Cornwall, with surely the most beautiful seaside views from any railway in Europe.

Feeling the urge to try something more historical? This Easter a full-size replica of Stephenson's Rocket is running passenger trips on 150m of specially constructed track near the Albert Memorial in London. Now here's a piece of railway line that Bob Crow will never be able to get his hands on.

Michael Williams's On the Slow Train: Twelve Great British Railway Journeys is published by Preface Publishing on 15 April at £14.99