LUCERNE, Switzerland - This is one Philadelphia Orchestra tour that nobody - not the rank-and-file musicians, not the guest soloists, and certainly not the festivals presenting them - is taking for granted, particularly in this picture-postcard city inhabited by the musical gods.

The long-planned 13-concert sweep through Europe's most prestigious festivals begins Thursday with the Grafenegg Music Festival outside Vienna, Austria, and ends Sept. 9 in Paris. While the tour was never said to have been in significant danger, everything has been open to question since the orchestra filed for Chapter 11 bankruptcy in April.

"Reading about all of the problems with the orchestra, I thought maybe this tour is not going to happen," said pianist Jean-Yves Thibaudet, who shares the tour's concerto slots with violinist Janine Jansen. "Almost from the beginning, the orchestra was quite firm in saying, 'Don't worry. We're really going to try to save this tour. It's important for the orchestra.' "

That's an understatement. The usual rationale for a European tour is a chance for an orchestra to prove itself in the places all the great music came from, measured against those who play it in an unbroken tradition that began with the composer. That's true in this tour's repertoire, ranging from Verwandlung No. 3, by modern composer Wolfgang Rihm, to Berlioz's Symphonie Fantastique. (Chief conductor Charles Dutoit, who leads the tour, has been a leading figure in Berlioz performance history.)

In the works since 2008, this tour had to happen, if only to keep from burning industry bridges.

"Whenever you're in a challenging financial situation, you have to analyze everything you're doing," said Stephen Millan, vice president and general manager of the Philadelphia Orchestra. "One of the things we've been saying to the public and media people is that the music has to go on."

The numbers, however, suggest that the next tour might not happen for a while. Though Europe's transportation costs are lower than those of, say, the 2010 Asia tour, industry axioms say the higher the prestige, the lower the pay. For an orchestra of Philadelphia's caliber, fees run between $75,000 and $150,000, making the estimated earned income about $1.5 million (compared with $2.2 million for Asia) - roughly half this tour's $3 million cost.

The value, however, is inestimable. This European festivals tour puts the Philadelphia Orchestra in the most exclusive classical music club on the planet: These dates aren't slots in a regular season, but showcases in what amount to musical utopias. Even Grafenegg, which has been in existence only since 2007, puts the orchestra in a highly distinguished lineup.

"The crème de la crème comes to Grafenegg," said its artistic director, Rudolf Buchbinder, one of Vienna's most respected concert pianists. "If this wouldn't be possible to do, I wouldn't run it."

In contrast to Grafenegg, which draws nearly half its audience from non-Viennese locals likely hearing the Philadelphia Orchestra live for the first time, the orchestra will arrive Saturday in Lucerne needing to live up not just to the standards of other honored guests, but also to a bar set even higher last weekend by the resident Lucerne Festival Orchestra. Known worldwide through recordings under the venerable Claudio Abbado, it is revered locally almost beyond comprehension.

At its performance of Bruckner's Symphony No. 5, the audience included conductors David Robertson and Pierre Boulez, and at the end Abbado was showered with flowers - not a few, but buckets' worth - while players hugged one another in congratulation. The audience continued applauding even after the musicians had left.

Were that not enough, the Philadelphia Orchestra is all but tag-teaming through Europe with the Chicago Symphony Orchestra, in its first tour with Riccardo Muti. They will come within hours of intersecting in Lucerne, and will do so again at Dresden Music Festival, another artist-run festival, under the esteemed cellist Jan Vogler.

Often, the Philadelphians are victims of their own success on tour, when, because of high fees and high ticket demand, they play in larger but less glamorous halls. That appears to be the case when the orchestra plays the Kulturpalast, a reputedly monolithic structure from Dresden's communist period, with a large-for-Europe seating capacity of 2,600. Vogler wanted as many as possible to hear the Philadelphians, and at ticket prices lower than those at the city's more prestigious Semperoper.

"People feel no barriers to go to this hall. They don't have to dress and be elegant," he said. There's a large audience to be tapped: In this city of 500,000, a third go to a classical music concert three or more times a year.

Many of the tour visits are single nights, such as Dublin (where the orchestra will make its debut Monday at the National Concert Hall), Berlin (where it will play Sept. 3 at the Philharmonie, home of the Berlin Philharmonic), and Frankfurt, at the hallowed Alte Opera House on Sept. 4.

One two-concert date is a big one, the Edinburgh Festival, another situation that hosts the best of the best. And one of the most crucial dates comes at the end - the Proms in London at Royal Albert Hall. Last year's season reached a record high of 18 million in radio and telecasts, according to BBC Proms director Roger Wright.

It's there, perhaps, that the Philadelphia Orchestra stands to reach its largest audience. And unlike in some cities, the orchestra won't be preaching to the choir: London is the home of Gramophone magazine, which ruffled many Philadelphia feathers several years ago when the orchestra not only failed to make its list of great ensembles, but also was mentioned only in a "past glories" section, with the long-defunct NBC Symphony. Gramophone has clout, so Philadelphia has something to prove, and will do so with at least two key magazine staff members in the audience.

To make the date, the orchestra, at that point long departed from Edinburgh, will have to jump back from Germany and then, for the tour's closing date, go to Paris.

"I do work hard at minimalizing the hopscotching, but sometimes it can't be avoided," said Millan.

Tours usually have provincial dates where the orchestra can get its legs, but this one has nowhere to hide, no room for an off night.

Or, for the glamorous Thibaudet, an off-looking night. Besides having set a high performing standard, Thibaudet has led audiences to expect him to look as great as he sounds. So he'll be the luggage king of the tour.

"I'm a Virgo, and Virgos are very organized and like to have things nicely folded and looking good," he explained. "Though I'm a very good packer, I've never found a way to travel light. I like having lots of things to choose from. And that takes a lot of room."

But you'll never hear him say tours are a pain, and certainly not this one, partly because he loves Liszt (the Piano Concerto No. 2 is on several programs), but mostly because he loves Dutoit.

"It's been 20, 25 years since we first played together, and it's always been so easy," said Thibaudet. "I always have a piano rehearsal with a conductor before the first [full] rehearsal. But Charlie is the one person in the world where I could arrive at the hall with no rehearsal at all and I wouldn't even be nervous."

Contact music critic David Patrick Stearns at dpstearns@phillynews.com.