The Orient Express: Hang on, Mum, I'm not sure we're on the right train

I'm on the wrong train! I'm about to depart Venice Santa Lucia for London Victoria on the Venice Simplon Orient Express to report on the 125th anniversary of the great European rail route. Yet the real Orient Express – pardonnez moi, the Express d'Orient – which first departed Paris's Gare de l'Est for Constantinople in October 1883, will leave Strasbourg at 10.20pm tonight bound for Vienna.

According to The Man in Seat Sixty-One – whose website is the authority on the iron horse, so he should know – the original service continues to ride the rails, but this is not it. The real Orient Express is the one that had its route cut short of Istanbul in 1977, then right back to Vienna in 2001, and since 2007 has whizzed passengers along the stretch between Paris and Strasbourg on the new high-speed TGV Est.

It seems the Strasbourg-Vienna train is the true heir. Why, some of the staff are still in the employ of the original operator, the Compagnie Internationale des Wagons-Lits. And there are benefits to travelling on it, too, says Mr Sixty-One, like the fact that you don't have to pay out big bucks – you can even use an InterRail pass – and you can get your head down on a couchette if your budget can't quite stretch to a sleeping car.

Do I care? This is the right train for my purpose; I'm going in search of the spirit of this journey not its provenance. I want to discover what it's like aboard the glamorous Orient Express that lives in our collective imagination, an experience only enacted on the train put into service in 1982 by James Sherwood, the former boss of Sea Containers, who knew how to turn a profit out of a fantasy.

That's why I'm boarding this train from London to Venice, (one of a range of routes offered), accompanied by my mum, who has won the golden ticket to join me on this jolly because it is her 80th birthday. She doesn't mind if it's not the Orient Express. She would far rather travel on this shiny royal-blue one with its sharply uniformed stewards.

Mum likes the mahogany panels with marquetry in pretty Art Deco floral designs. She likes the little cabinet in the corner with its old-fashioned washbasin. She even likes the geometrical shapes in the chrome luggage racks (well, I did have to point those out). But, most of all, she's very comfortable on the settee-cum-bed, with its big cushion and broderie anglaise antimacassars, and will be quite happy sitting here watching the Alps go by, thank you very much.

Our surroundings are indeed splendid, the result of the £11m and 23,000 man hours invested in refurbishing the authentic Wagons-Lits LX-class carriages, which date from the Twenties and Thirties.

First, they took off the sides and the roof to check the soundness of the structure of each of the 11 sleeping cars, three dining cars, bar car and two service cars that make up the quarter-of-a-mile-long train.

Then they adjusted the bogies and suspension and reinforced the brakes, replaced the bearing boxes and batteries, updated the electrics, plumbing and heating, modified the kitchen and found room for wine cellars and linen storage, re-upholstered the seats and beds, and brought the train up to today's safety standards.

Of course, these improvements are not obvious to the eye, but they are felt in the smooth running of the train. More apparent to passengers is the careful restoration of the interiors, especially in the three dining cars, which feature the work of several Art Deco designers, including Rene Lalique, whose panels of glass depicting bacchanalian maidens decorate the exotically named Cote d'Azur restaurant carriage.

We have three sit-down meals to eat before reaching the English Channel – when our journey will be rudely interrupted as we are disgorged on to a coach to travel on Eurotunnel before joining the equally attractive British Pullman for the final leg of our journey – so passengers get the chance to take a closer look at his work and that of the other craftsmen, over dinner or lunch here and in the Etoile du Nord and Chinoise dining cars.

This tourist train is no imposter: if the authenticity of the carriages isn't persuasive enough, its inspiration is clearly the Simplon Orient Express – the star of Agatha Christie's great mystery, Murder on the Orient Express. One of a network of routes spawned by the Express d'Orient, between 1919 and 1962 the Simplon Orient Express provided a glamourous way to travel from Calais to Paris, Milan, Venice, Trieste, Zagreb, Sofia, Athens, Istanbul and variations therein.

The VSOE is the train we all really want to travel on because the point is not just to transport yourself from Venice to London, or vice versa; it is to transport yourself into the past, to an elegant yesteryear populated by royalty and celebrities, femme fatales and spies. Show up in the bar and you'd better be wearing your gladdest rags – and jewels if you have them. These days, it may be the business community of Middle England gathered around the baby grand, but they're self-cast as the characters from the train's heyday.

We sold the Simon diamonds some time ago, and don't tell Mum but this trip costs £1,550 a head each way. But such a steep fare is surely a help rather than a hindrance for sales; it firmly establishes that you've splashed the cash, that the experience is a milestone trip taken to celebrate birthdays, anniversaries and other assorted special occasions. Everyone knows it costs a bomb for a ticket on the Orient Express – that's a very potent way to say I love you, and it will guarantee the oohs and aahs of the neighbours.

Take a tip. If you really want to impress, lay on the works by starting your trip at the Hotel Cipriani in Venice, which is also owned by the Orient Express people. Arrange a water transfer from the airport in order to arrive in style, taking in this sinking city's glorious architecture from its canals.

Drop your bags and take the private launch to the Piazza San Marco for a stroll, followed by an exorbitantly priced cappuccino to the strains of a string quartet at one of the cafés on the square, or a traditional Bellini – prosecco with peach juice – at the similarly expensive Harry's Bar on the waterfront. It's got to be done, whether you've taken your mother, brother or lover.

Return to your opulently furnished room at the Cipriani, or the Cip (that's "chip") as it's called by the people with Swiss bank accounts who can afford to be returning guests – it has been the favourite Venetian retreat of visiting dignitaries and celebrities for the past half-century. Hopefully, you have booked a room with a view of the lagoon, and try to get one in the recently refurbished wings. The hotel turned 50 this year, and in true middle-aged tradition is marking the occasion with a facelift. A rolling three-year revamp is refreshing bathrooms, updating the technology and lavishing flourishes in Murano glass, Carrara marble, cashmere and silk. Then dress for dinner at the formal Fortuny restaurant, or the more relaxed Cip's Club terrace, over the water, which looks back at St Mark's Square.

What a wonderful evening. And what a wonderful trip is still ahead for us and the other combinations of friends, relatives and lovers converging on Venice's main railway station, where on Wednesdays and Saturdays between March and November the train departs at 11.10 sharp for London.

Luggage stowed and boarding card in hand, there's just a few minutes' grace before departure for photographs on the platform in front of those gleaming royal-blue carriages.

"Please, it is time to get on board," calls our steward, Amaury. And we're off.

COMPACT FACTS

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Kate and Sted Simon travelled as guests of Orient Express (0845 077 22 22; orient-express.com). The three-night "Venetian Serenade" package from the Journeys of Distinction 2009 brochure starts at £2,360 per person, based on two sharing, including a flight from London to Venice, transfers, two nights at the Hotel Cipriani, and a journey on board the Venice Simplon Orient Express from Venice to London. Return flights to Venice with bmi (0870 6070 555; flybmi.com) cost from £76 in the Better for Business sale if you book before 30 September.

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