It’s the middle of the night and I’m prodded awake by a rowdy Russian on the bunk below, who insists we share his bottle of vodka. After refusing half a dozen times, I sleepily toast Mother Russia, his health, my health and the beauty of Lake Baikal. Soon he passes out, snoring like a steam train, leaving me wide awake until morning.

That was in 1999. Few people go on a once-in-a-lifetime trip twice but I’m back on the Trans-Siberian Railway. This time, though, things are rather different. My single compartment is fit for Russian royalty or, as the passenger logbook puts it, “You are travelling in an ambience in which Soviet VIPs would have felt at home – but with the comforts of the 21st century.”

“Trans-Siberian” refers not to the name of a train but to a railway line that snakes across Russia from Vladivostok to Moscow, a distance of 9,258km. My route, starting in Mongolia, cuts a hefty slice off the journey to Moscow and offers a snapshot of the world’s least densely populated country into the bargain.

Ulan Bator isn’t Hong Kong, but it wants to be. The capital of Mongolia is enjoying a resources boom that has translated into gleaming towers and a roll call of stylish stores, fancy restaurants and fashionable nightclubs. Giant screens beam Bloomberg at bow-legged nomads whose ungainly waddle is at odds with the dignified poise they show on horseback.

Sukhbaatar Square is a large, traffic-free oasis surrounded by an increasingly congested city. Performance cars rev at stop lights and advertising hoardings hog commercial frontages. “Winter Time is Pepsi Time,” wins the prize for shrewdest marketing ploy – Ulan Bator is the world’s coldest capital.

In the centre of the plaza, a bronze likeness of Mongolian independence hero Damdin Sukhbaatar extends his arm expansively at all the glass and concrete as if to say, “I remember when all this used to be fields.” Nearby is a statue of that ruthless conqueror Chinggis (Genghis) Khan – a man and now a brand whose name adorns more places and products than a modern-day multinational. I landed at Khan Airport and have a room at the Khan Hotel, from where it’s a short walk to the Khan Irish Pub, which serves Khan Beer and Khan Vodka. I change dollars into tugriks at a branch of the Khan Bank but skip the eponymous restaurant, nightclub and chocolate bars.

Naadam, the raucous Mongolian summer games festival, is still two weeks away but a mini version is taking place in Gorkhi-Terelj National Park, a two-hour drive from the city. The event is also a chance to meet some of my travelling companions.

I’ve been assigned to an English-speaking group of 12, including Australians, New Zealanders, Brits and Singaporeans, who all joined the train two days earlier, in Beijing. After a meaty lunch, we get to see a wrestling match, an archery demonstration and a horse race. I keep a low profile – events like this tend to finish with a member of the audience being invited to wrestle the local champion.

We’re dropped off at Ulan Bator railway station and I set about locating my home for the next eight days. The privately operated Tsar’s Gold train travels along the same rails as the public service, but that’s where the similarity ends. There are 174 passengers in all; grouped together by language for the excursions but dispersed throughout the train according to accommodation preference. Categories range from the luxurious ensuite Bolshoi Platinum cabins to Nostalgic Comfort and Superior rooms with shared facilities.

Tatiana and Svetlana are my carriage attendants. They provide endless cups of complimentary tea and coffee and attempt to give me a grounding in spoken Russian. The girls also transform day compartments into cosy bedrooms while we enjoy dinner; then repeat the process in reverse during breakfast. I unpack and borrow War and Peace from the carriage library. Only 6,266km to go.

Comfort aside, there are a number of advantages to travelling in the style of a tsar or a Politburo apparatchik. At 3am, we reach the frontier between Mongolia and Russia, where immigration officials board the train and handle passport formalities at our bedsides. (When was the last time you were in pyjamas while your passport was stamped?) A cursory look around my room satisfies border guards that I’m not smuggling a huge shipment of Khan cigarettes and before long we’re on the move again.

The courteous, efficient operation reminds me with a shudder of my previous experience at this station. In 1999, I spent seven hours in a chilly hut surrounded by scores of inebriated traders and mounds of merchandise that were painstakingly inspected by overzealous customs officers.

By breakfast we’re making steady progress through the Republic of Buryatia, an autonomous Russian region where the faces and language are still Mongolian. In the capital, Ulan-Ude, we receive a warm welcome in more ways than one. The mercury is nudging 36 degrees Celsius, which comes as quite a surprise. Growing up in England, I remember forecasters blaming every malevolent blast of icy weather on a spiteful, faraway place called Siberia. It turns out that summers here can be as hot as the winters are cold.

Ulan-Ude proves to be an easy-going introduction to Russia, notable for an enormous Lenin head with distinctly Asian eyes that overlooks the main square. There’s also a first chance to see onion-domed Orthodox churches. It won’t be the last. We separate into our groups to explore the city before meeting up at the Opera and Ballet Theatre for an all (throat) singing and (Cossack) dancing concert.

Back on the train that evening, a sense of eager anticipation pervades the dining car. We’re due to arrive at legendary Lake Baikal in the morning.

Some passengers can barely contain their excitement and retire for an early night like kids on Christmas Eve.

Construction of a rail link between European Russia and the Pacific began in 1891 and was eventually completed in 1916. Obstacles were numerous and in some cases almost insurmountable.

Mile-wide rivers had to be bridged, forests negotiated and swampland drained. Permafrost and mountains needed dynamiting. Labourers including convicts, who were given time off their sentences, had to deal with winter temperatures that dipped to minus 40. Cholera and bubonic plague decimated a workforce that also suffered from attacks by bandits and even tigers.

Bandits were also a problem for early passengers. English writer Annette Meakin journeyed through Siberia with her mother in 1900 and explained in her travelogue, A Ribbon of Iron, that she was deemed “bold if not rash to travel without a revolver”. The adventurous pair were accompanied by soldiers for one particularly hair-raising leg of the expedition. “They sprang out the moment the train stopped, no matter whether there was a station or not and stood with shouldered bayonets.”

From an engineering perspective, the section along the southern tip of Lake Baikal was the most problematic. Before completion, a steamer was used in the warmer months to ferry passengers across the lake from where they could continue by rail. Things weren’t so straightforward at other times of the year, however. Writing in 1903, American Michael Myers Shoemaker described the challenges of a winter crossing: “It is a matter of grave doubt whether we can cross the Baikal, or rather whether the icebreaker can force its way through. If not we shall be transferred to sledges for the remainder of the passage.”

Like a cruise ship, the Tsar’s Gold does the hard miles while we sleep, leaving us refreshed and ready to explore during the day. In 1999, I chugged past all the photogenic parts of the route in the middle of the night; this time I awake on a gorgeous summer morning to discover we’re riding alongside Lake Baikal. Sitting in the locomotive with the driver is a spectacular way to appreciate some of the 33 tunnels and 200 bridges that required such ingenuity to build and cost so many roubles.

Today’s excursion begins with a boat ride and the stats are soon coming thick and fast. The 640km-long body of water is the world’s deepest and oldest. It contains one-fifth of the world’s fresh water – enough to keep every person on Earth in H2O for 50 years. Best of all, though, according to Siberian superstition, anyone who swims in the Baikal’s chilly blue waters is rewarded with an extra 20 years of life.

That evening, we relax at a convivial lakeside barbecue. Everyone is in high spirits, thanks to the beautiful location, the odd glass of vodka and the bonus of suddenly feeling two decades younger. The Chinese passengers get things going with a song and the German contingent follows suit. The English-speaking group chooses not to belt out a tune; most of us would sooner wrestle a Mongolian.

The citizens of Irkutsk look as though they’ve never been for a life expectancy-lifting swim. Despite the warm weather, faces are pinched and pale as if they’ve seen things that people shouldn’t have to see. The city once known as the Paris of Siberia has a dark history as a transit hub for the notorious forced labour camps (gulags) and a bright future thanks to vast mineral wealth. We visit the Volkonsky Museum, renovated home of an aristocratic family exiled after the Decembrist revolt of 1825. The wooden property is filled with original possessions and has the feel of a doll’s house, particularly during a spine-tingling candlelit concert.

From Irkutsk, there are still 5,192km to Moscow but I’ve stopped using distance as a means of measuring my progress. Instead I estimate there are another 17 meals before we reach Russia’s capital. The sheer size of the world’s largest country is overwhelming. Siberia alone comprises more than 8 per cent of the planet’s landmass, with a population slightly smaller than that of Shanghai. Featureless grasslands stretch into oblivion and the setting sun paints never-ending clumps of silver birch trees a burnished gold. We pass isolated villages, each house boasting a backyard banya.

The home-made saunas look ridiculous in the shimmering summer heat but there is no better place to hole up when the Siberian winter descends.

At one nameless halt, I get off to stretch my legs on the platform, keeping a watchful eye on the time. As I compare being abandoned at a remote Siberian railway station with being shipwrecked, a local train pulls in. A man in his underwear stares out of a filthy window, yawns, scratches himself and flops back onto his berth. I return to my cabin and ask the ever-obliging Tatiana for an espresso.

Time rarely drags aboard the Tsar’s Gold. There are history lectures, Russian lessons and a vodka tasting session, which is predictably oversubscribed.

We learn that you should enjoy the “holy water” in company, as only alcoholics drink the stuff alone. I make a note to stop swigging from the complimentary bottle in my room.

Novosibirsk is Russia’s third largest city by population, yet the university town didn’t exist until a railway bridge was built across the mighty River Ob. Sightseeing options include a good selection of museums, the Alexander Nevsky Cathedral and a group of protesters holding up placards for peace in Ukraine, who become involved in a war of words with an argumentative passer-by.

Travel writer Colin Thubron described the Ural Mountains as “too shallow to form a frontier, let alone the divide between Europe and Asia”.

The border is a blink-and-you-miss-it event from the train, so it’s best to get off. An obelisk west of Yekaterinburg straddles the two continents and marks the spot where tourists and newlyweds take it in turns to pose for obligatory “one foot in each continent” photos. Champagne flutes appear from somewhere and we toast our progress as if we have cycled all the way from Mongolia.

Feeling inappropriately tipsy, we arrive at the Church of All Saints, which was built on the site where the last emperor of Russia, Nicholas II, and several members of his family and household were slaughtered by the Bolsheviks during the civil war. DNA analysis confirmed the identities and, in 2000, the Imperial Romanovs were canonised by the Russian Orthodox Church.

In the restaurant car that evening we put our watches back another two hours and finish dinner before we started. Conversation takes a similarly surreal turn. We wonder what percentage of the world’s population has ever taken a shower on a train and that if Russia really is home to about 20 per cent of the world’s trees, who actually counted them.

Tatiana and I are getting on like a house on fire. She and I communicate through a combination of sign language, sketches and, as a last resort, mime. We discover we’re the same age and draw matchstick boys and girls to represent how many children each of us has. She’s holding a trashy paperback so I claim the literary high ground by showing off my borrowed copy of War and Peace. I have no intention of reading the daunting 1,444-page Tolstoy classic but there’s never a right moment to admit this to her.

Kazan is a rewarding detour from the main Trans-Siberian route. The capital of Tatarstan is home to half a million Volga Tatars, a Turkicspeaking ethnic group, and both Tolstoy and Lenin studied at Kazan Imperial University.

Within the sturdy white stone walls of its kremlin lie a mosque, a cathedral, museums and a Pisa-style leaning tower. We sit spellbound through a flawless performance at a music school for gifted young children, then it’s back on the train to clackety-clack over the Volga River at sunset.

Light rain greets our arrival in Moscow but doesn’t prevent us from doing the tourist thing one last time. We stroll across iconic Red Square to St Basil’s Cathedral, which looks almost edible.

Then it’s down into the Metro, a busy public transport system but also a chandelier-strewn underground art museum filled with marble columns, bronze sculptures, frescoes and stainedglass windows.

Marching behind a flag-waving tour guide is not my cup of tea and at the Kremlin there are more flags than at an Olympic Games opening ceremony. Initially I had some concerns about the impact our 174-strong party would have at sightseeing attractions. I needn’t have worried. We split into small groups at each destination, reuniting only for performances and concerts that wouldn’t have gone ahead had there only been a dozen of us.

In an age of jet travel, the Trans-Siberian Railway reintroduces the concept of geographical distance. It’s an exhilarating, culturally rich experience spanning six time zones and thousands of kilometres. I’ve been educated and informed; pampered and spoilt. And I’ve realised that sharing a sleeping compartment with an alcoholic Russian is so 1999!

Country Holidays (www.countryholidays.com.hk), without which this article wouldn’t have been possible, specialises in high-end exotic holidays, including luxury train journeys, and offers a variety of itineraries from Beijing to Moscow aboard the Tsar’s Gold. Extensions and bespoke sightseeing tours can be tailored to suit individuals or small groups.