India has always reveled in the glamour of her trains, and The Deccan Odyssey is the jewel in her crown. Turbaned valet on hand, Lawrence Osborne rides the gilded rails from Mumbai to the beaches of Goa, with a side trip to the fabled treasures of the Ajanta Caves

Mumbai's Victoria Station could easily be the London of a century past. Outside, its Gothic gargoyles peer into a tropical city in the middle of one of the greatest booms of the new century. Mumbai roars and snarls with its newfound swagger—Maximum City, as local writer Suketu Mehta calls it in a recent exposé. Inside Victoria, the trains are lined up like greyhounds about to be let out onto a track, while vast crowds from the megalopolis mill around them. However, there is an island of quiet. The Deccan Odyssey, one of India's most regal luxury trains, sits apart from the commuter business, a dark-blue snake of carriages whose walls carry a gold insignia of crossed sabers.

Some think that this will be India's century. Given the country's near double-digit growth and its population of a billion bursting with the largest concentration of engineers and doctors on earth, how—they ask—could it not be? And as new wealth pours through an ancient society, the rising middle class needs its status symbols. You could argue that The Deccan Odyssey is one of these, and it is, in any case, no ordinary train. It's where Indian millionaires and foreign tourists go to live out an idea of luxury, to have themselves escorted through rural India with a turbaned valet at hand, acting out a maharaja fantasy of sorts. As India booms, it seems, there's so much wealth in places like Mumbai that the $2,450-per-head price tag is no longer a big deal. The Deccan is a horizontal hotel in perpetual motion, a counterpart to other legendary Indian trains like the Palace on Wheels, and for seven days it whisks passengers through India's third-biggest state, Maharashtra. The state stretches all the way from Mumbai to Goa along the Arabian Sea, and sprawls inland to encompass the vast mountainous plateau called the Deccan, one of India's archaeologically richest areas. It's a route I chose because it seemed to straddle the old India and the new: from the Maximum City to the oldest Buddhist art at the caves of Ajanta, with countless stations in between.

Moreover, train travel has always been one of India's blessings. Nowhere else do you find these grande dame trains with all their anachronistic trappings—their silver tea services and turbaned staff, their air of cranky elegance. Most emerging superpowers have let their railways decline, but India is the exception. She seems to revel in the glamour of her aging railways.

My valet was called Pramon. The Deccan staff are costumed in a dark navy that matches the carriages, with two-horned traditional hats covered with a gold net. They look a little uncomfortable in this eye-catching gear, but their manners are practiced and imperturbable. Pramon put a garland of flowers around my neck, presented me with a kiwi-colored cocktail, and took my hand as though I were a wayward child who needed to be shown around a very big, very complex maze.

"If you get lost," he said, jiggling his head, "I am here to show you."