In the Orient Express lounge at Ostiense station in Rome, my train leaves in an hour but the high living is already under way. There are glasses of iced Veuve Clicquot and Italian mid-morning snacks, alongside gorgeous marble bathrooms that invite one to linger over the artisan soaps, the soft towels, the fresh flowers. A trio of piano, saxophone and double bass serenades passengers with a medley of cool jazz standards, among which I recognize a Duke Ellington classic, “Take the ‘A’ Train.”

What I’m about to take is an A train in another sense altogether. Unveiled with great ceremony, La Dolce Vita is a new iteration of the Orient Express marque, raising the bar for rail travel to heights rarely scaled even in the splendiferous 140-year history of the brand.

The elegantly refurbished blue-and-brown exterior of La Dolce Vita’s carriages.

In the humdrum surroundings of this suburban-line station, the newly refurbished carriages, gleaming in their smart blue-and-brown livery, give off alpha waves of sophistication. At 12.07pm precisely the train pulls out of Ostiense to embark on a 24-hour round-trip journey entitled Tastes of Tuscan Vineyards—one of eight La Dolce Vita routes (all within Italy) that will be available by the end of this year.

We cross the Tiber, slinking through Trastevere station where a group of locals gawp open-mouthed as the train glides by. I settle into my suite, a substantial cabin incorporating a double bed with crisp cotton sheets, a small sofa, a lacquered table and leather-upholstered swivel chairs, a miniature bar and a bathroom with a power shower.

The train’s bar car, where expertly mixed Negronis are a highlight.

The train’s interior, designed by the Milan-based masters Dimorestudio, avoids the chintzy maximalism of the brand’s fin-de-siècle origins in favor of a sleek, chic evocation of mid-20th-century Italian style, the curvy retro shapes and glossy surfaces channeling designers such as Gio Ponti and Gae Aulenti. The references are telling: in the low-lit corridor outside my cabin, black-and-white photographs by the society snapper Marcello Geppetti (the original paparazzo) reflect the gilded 1960s world of Federico Fellini and Marcello Mastroianni, of Gina Lollobrigida, Sophia Loren, and Claudia Cardinale.

Lunch, served in the all-white dining car, is a multicourse affair created by the chef Heinz Beck, whose restaurant, La Pergola, holds Rome’s only trio of Michelin stars. Banish all thought of regular rail food: this is by some way the most lavish, but also the most delicious, collation I’ve eaten on board a train, nimbly served by uniformed waiters (no overspilling soup bowls here) and accompanied by fine Italian wines. Beyond the window, postwar housing blocks gradually give way to a landscape of open fields, stone farmhouses, vineyards and umbrella pines.

A deluxe room aboard La Dolce Vita.

The original Orient Express made its maiden voyage in 1883, linking European cities from Paris to Istanbul in a service that, especially after being immortalized as a crime scene by Agatha Christie, became a byword for glamour and intrigue. This route ran until 1977, then the service petered out in 2009, having become a series of shorter routes operated by Belmond under the name Venice Simplon-Orient-Express.

Somewhat confusingly, the French hotel giant Accor has reactivated the Orient Express brand per se, using it as an umbrella for high-end hospitality projects that include the Italy-based La Dolce Vita train and the historic La Minerva hotel in Rome, which has recently been given a stunning new lease of life. (Slated for later this year are a Venice hotel, the 15th-century Palazzo Dona Giovannelli, and a sailing yacht, the Corinthian, said to be the largest in the world.)

Guests can lounge on the beds in a post-breakfast glow, idly watching the spring-green Tuscan countryside slide by.

Halfway through the afternoon we pull into a country station serving the hill town of Montalcino, where the program features a visit to the aristocratic wine estate at Argiano. (La Dolce Vita journeys are the closest thing on land to a kind of hyper-exclusive cruise, with bespoke gastronomic and cultural visits instead of harbor stops.) The visit begins with a private tour of the Renaissance art collection amassed by Argiano’s owner, the Brazilian magnate André Santos Esteves, followed by a tasting in the estate’s 16th-century cellars and a magnificent dinner in the grand hall.

Probably a higher degree of railway luxe exists somewhere in the world, but it’s hard to imagine where or how. A detail that impresses me are La Dolce Vita’s next-level guest amenities: the bathroom soap from heritage soap makers Eredi Zucca in Milan comes neatly wrapped in tissue paper and tucked inside a cobalt-blue box; a leatherbound notebook from the Florentine stationers Pineider is monogrammed in gold with my initials. A highlight of this Tuscan trip is returning from a night-time negroni in the bar to discover a pair of pointy-toed velvet Friulane slippers (made in Venice) waiting for me on the down-turned bed, along with a saffron-scented macaron, should I feel peckish before snuggling down into those cool cotton sheets.

The luxurious suite aboard La Dolce Vita.

Life aboard the Orient Express is a heady experience of contemporary travel at a level of opulence that feels almost surreal. But for me the best thing about La Dolce Vita is the dolce far niente—the sweetness of doing nothing. Simply to lounge on the big white bed in a post-breakfast glow, idly watching the spring-green Tuscan countryside slide by, soothed by the motion of the train as it rolls back to Rome and reality, is genuinely as good as it gets.

Paul Richardson is a British food-and-travel writer