When Karl Marx urged the workers of the world to unite he never thought they'd be whistling while they worked. At Shanghai Disneyland Mickey Mouse and the revolution join hands in a way not scripted in the Communist Manifesto.

Mainland China's first Walt Disney resort, spread over 4sq km at a cost of €5 billion, is carefully aimed at entertaining the swelling ranks of the middle class in the world's second-biggest economy.

The US firm’s biggest overseas investment, which it says will be the planet’s most visited Disneyland, embraces six themed lands, a shopping district and almost 100 acres of gardens, lakes and parkland teeming with 2.4 million plants.

An amble past the merchandising stands takes you to the Enchanted Storybook Castle, the biggest Disney castle in the world, where a group of young Shanghai women wearing frilly dresses, dangerously high heels and Minnie Mouse headbands photograph each other furiously. A major collision is averted by a ban on selfie sticks.

The Li family, who live not too far from the resort, in Pudong, are having a great time. “This is great, fantastic! We will come every week, even just to go shopping in Disney Town,” says Mr Li, a businessman. His teenage daughter and wife nod enthusiastically. Behind them a small parade is moving along Mickey Avenue, as Main Street is called here. “Normally, we have to go to Hong Kong or go overseas to get this kind of quality. This is great.”

For the park to succeed it needs to lure China’s newly wealthy, and the whole event is a profoundly middle-class experience. In the high-speed-rail station in Beijing, boarding the sleek train that will whizz us to China’s financial capital, 1,300km away, in less than five hours, one is struck by the crowds but also by the fact that the travellers are all middle class.

The only ones who look as if they have come from the countryside are the slightly bewildered parents shuffling across the gleaming concourse behind their successful, Rimowa-suitcase-bearing urban children. The familiar travellers – people dragging canvas bags stuffed with textiles through the turnstiles, or dusty families arriving in the capital to make their fortune – are absent from this station. This high-speed network is expensive, for those beyond the tens of millions of migrants on the move.

Trudging through the Shanghai heat into the Garden of Imagination, our first sight is a performance of Golden Fairytale Fanfare, a brilliantly produced , frantically paced “musical celebration of Disney princesses”. At one point Anna and Elsa from Frozen are singing a mash-up of Let It Go and For the First Time in Forever. One fears the hearts of the gathered preteens might burst. Not far from the Hunny Pot Spin, a gentle whizz in Winnie-the-Pooh honey pots, is the Evergreen Playhouse, home to Frozen: A Sing-Along Celebration, where wannabe Annas and Elsas can really let it go.

Although many of the princesses are played by western actors, most of the 10,000 employees – or cast members, as Disney calls them – are Chinese. They’re working in a growing market: although China’s economy is slowing, tourism continues to expand: spending is set to triple by 2020, after industry investment jumped 42 per cent last year. About 330 million people live within a three-hour train journey of the resort; Disney expects up to 12 million people to visit in the first year.

“We thought it was excellent,” says Brendan Brophy from Carlow, who runs several bars and restaurants in the city and who is here with his wife, Joyce, her mother, Jan, and their son, Keelan, who is turning four this week. “Keelan loved the interaction with the Disney characters, and he thinks Daddy is friends with Goofy,” says Brophy.

“It will be 99 per cent Chinese that will visit the park, especially from other provinces on family tour groups.” The park is “well laid out, to try to spread the crowd,” he adds, “but if you go for the day you can probably reckon on going on three things.”

The staff deal calmly with the sometimes stressful complaints. “I loved how they stayed in character,” Brophy says. “I asked Jack Sparrow from Pirates of the Caribbean where I could get a cold beer, and he just pointed at all the restaurants and said, ‘There is rum everywhere, lad!’ without batting an eyelid.”

The local government is directly or indirectly the chief investor in the resort, which is in Pudong, an area of marshland across the river from the old part of Shanghai that has been turned into a modern megalopolis in less than three decades. The father of the late writer JG Ballard worked in a factory here in the 1930s. Neither Ballard would recognise it now.

The main shareholder in the resort is Shanghai Shendi Group, which owns 57 per cent. Shendi consists of four big state-owned enterprises: Shanghai Media Group, the hotel chain Jin Jiang, the retail group Bailian and the property developer Lujiazui Development Group.

A child’s pass costs 399 yuan, or about €53, and an adult pass costs 499 yuan, or about €67, which is in line with prices at Disneyland Paris. It was still possible to buy tickets a few days before going.

At the Tangled Tree Tavern the usual fish and chips are matched by dishes aimed squarely at the local palate. The Sichuan chicken and chips are cooked with big chilis and Sichuan pepper; there is also a tasty Mongolian beef dish; an outlet nearby offers Mickey Mouse-shaped Peking duck pizza.

Outside the Festival Forest, where children try to pull a sword from a stone as adults pause for breath on the grass, a group of troubadours are singing The Dwarfs’ Marching Song in Chinese and playing lutes and lyres, but also using an erhu, a traditional stringed instrument.

After run-ins between mainland Chinese and Hong Kongers in the Disneyland there, attention had focused on how people would behave, and whether public urination and general loutishness would spoil the Shanghai resort. On our Sunday at Shanghai Disneyland people are friendly and generally well behaved. I see just one instance of a child peeing, and a single, shame-faced smoker sneaking a cigarette near the bins at Treasure Cove.

Disney has 7sq km at its disposal in Shanghai, and it’s already starting to expand. The existing 4sq km is already bigger than planned, as the wild popularity of Frozen in China spurred the company to expand its plans to give more Anna and Elsa oomph.

The park does not feel as crowded as the Hong Kong resort, and the average visitor is different: here lots of single children in buggies are being whizzed around by their parents.

The queues for the Tron Lightcycle Power Run, one of the fastest Disney rides, are huge, but the Star Wars Launch Bay is easy to get into. The most recent Star Wars movie did well here – Disney now owns Lucasfilm, the company behind the series, meaning that Princess Leia is now just another Disney princess – but other Disney franchises, including Marvel movies such as Iron Man and Captain America, are bigger hits.

We are sent away from the Launch Bay by cast members who are wearing orange Rebel Alliance jumpsuits, swishing light sabres and shouting cheerfully, “May the Force be with you.” It feels like the end of a religious ceremony as we trudge back into the real world.