Wes Anderson's new film, The Darjeeling Limited - a train movie featuring three brothers on a bonding exercise - follows the quirky pattern of Rushmore and The Royal Tenenbaums, and adds a vital new ingredient. The director tells Michael Dwyerabout his passage to India

Appearances can be deceptive. Wes Anderson is 38, but looks 10 years younger. He is preppy and unfailingly polite, and sounds like he comes from New York, where he now lives, but he was born and raised in Houston, Texas.

His fifth feature film, The Darjeeling Limited, is characteristically picaresque, but warmer and with a more affecting emotional core than his earlier movies. It would seem that a change of scene - the new film is set in India - brought out the romantic and the humanist in Anderson, just as making Before Sunset in Paris mellowed his fellow Texan director, Richard Linklater.

Anderson says he discovered India through movies, specifically Jean Renoir's The River (1951), and the work of the great Indian filmmaker, Satyajit Ray.

The Darjeeling Limited takes its title from the name of the train on which three estranged American brothers - Owen Wilson, Adrien Brody and Jason Schwartzman - travel through India as an attempt at bonding a year after they last met at the funeral of their father. The youngest brother, Jack (Schwartzman), is a writer who denies he drew on their experiences for his short stories, even though his brothers easily spot familiar references.

"That was very much our process," Anderson says. "We were very deliberate about drawing on personal experience for this movie and keeping it as personal as it could possibly be. And then it became part of our story to have Jack trying to use these events to make fiction and to get to the next chapter in his life."

A recurring gag involves Jack eavesdropping on his ex-lover's answering machine messages. Where did that come from? "I know someone who has done that," Anderson laughs, "but I don't think it would be right to indicate which collaborator offered that."

As it happens, Anderson has a younger brother, a writer and illustrator, and an older brother, a doctor. "I would be the Adrien Brody brother," he says.

The brothers travel with an impractical number of distinctive suitcases (designed by Louis Vuitton), which, I suggest, symbolises all the personal baggage they bring with them. "I don't like people referring to it as baggage, although I take your point," Anderson says. "It's unfortunate that that's the metaphor because it makes it seem very literal. They take their emotional baggage with them, but to me, the suitcases represent their father, who owned them. They're hanging on to them because he's gone and this is a way of staying connected to him."

The film mostly features actors who have acted in at least one earlier Anderson movie - Wilson, Schwartzman, and Anjelica Huston and Bill Murray, who have cameos this time - with Brody as the newcomer. "Owen and Jason have been friends of mine for years," Anderson says. "I'd wanted to make a film with Adrien for some time, and he really fitted in with us. He found his place and became a great part of the team."

Wilson collaborated with Anderson on the screenplays for his first three movies (Bottle Rocket, Rushmore, The Royal Tenenbaums) and acted in all three along with The Life Aquatic with Steve Zissou and The Darjeeling Limited. The US release of the new film coincided with Wilson's highly publicised suicide attempt. How is he now? "Owen is good," Anderson says. "He's in good shape. He's definitely on to the next chapter."

In The Darjeeling Limited, Wilson plays the brother who organises the India trip. He is such a control freak that he orders meals and drinks for his brothers and has an assistant named Brendan who draws up their precisely detailed daily schedules.

Did Anderson plan the production with the thoroughness of Brendan? "I guess every movie is organised like that," he replies. "Our approach with this was to make our careful plan, but we would not try and fight whatever went wrong. India is a place where often you are stunned at the last minute by how someone has interpreted what was agreed. It's a radically different culture from the one an American movie company is used to. I decided that whatever happened, we would incorporate it into our story."

Compounding the risk factor was Anderson's determination to shoot the movie on actual trains rather than using sets. "I knew things could go wrong," he says, "but I was happy we were leaving ourselves open to surprises. I wanted the surprises. And I didn't want to bring everyone to India and be locked into a studio every day. I expected that by going on a real train, every day would be an adventure, and it really was. It wasn't challenging in any negative way. It was very difficult to get the train in the first place and to prepare everything, but the actual shooting was very exciting. It's always hard to make a movie, but this one was never frustrating."

To what does Anderson attribute the enduring appeal of train movies? "There's a mystery about them," he says, "being locked inside a confined space with all these people on the way somewhere, but able to move around much more freely than on a plane. You have private spaces on a train and you can go to dinner. It's a bit old-fashioned because people don't travel by train so much anymore."

Asked about his favourite train movies, Anderson cites Twentieth Century with Carole Lombard and John Barrymore, and Hitchcock's The 39 Steps, The Lady Vanishes and North by Northwest. Showing with The Darjeeling Limited is Anderson's self-financed companion short film, Hotel Chevalier, set in a Paris hotel room and featuring Schwartzman and Natalie Portman.

"I had written that separately, but the more I worked on the other screenplay, I started linking them back and forth," Anderson explains. "I shot the short a year earlier because I had Jason available and Natalie said she would do it. Even when we were shooting, I had a suitcase made for Jason because I knew we were going to have to match the suitcases from the movie."

Anderson is already immersed in directing his next film, which is animated - The Fantastic Mr Fox, based on a Roald Dahl story.

"We've just recorded the voices - George Clooney plays the fox - and we're working on the animation in London now. I always liked this story. When I was growing up, my brothers and I had the book and it made a strong impression on me. A while ago I adapted the book with Noah Baumbach, an old friend and collaborator of mine. I really liked the way the script came out, so I decided to see it all the way through and to direct the film."

The Darjeeling Limited opens next Friday