How do you follow up a merry-go-round? If you're Marc Jacobs at Louis Vuitton, you get your people to build an old-fashioned train car. From scratch. The steam engine it was attached to pulled into the Cour Carrée a few minutes after ten this morning. One by one, Jacobs' models de-boarded wearing outfits straight out of the golden age of railroading, followed by porters carrying as many as three bags per girl. The news on the bag front this season is their oversize proportions and exotic fabrications. "It's just a trip," Jacobs said afterward, but you could tell even he was chuffed by the grand spectacle of it all.

Longtimers in the crowd remembered a John Galliano couture show for Dior, the one where a train stuffed with supermodels steamed its way into Paris' Gare d'Austerlitz. The more interesting echo today was with Miuccia Prada's show in Milan, where she too put skirts, dresses, and coat-dresses—likewise embellished with enormous crystals—over cropped pants and platform pumps. Here, as there, the elongated silhouette created by all that layering was quite strong—Stephen Jones' squashed hats added a good six inches of height.

Even if the look didn't strike you as a modern proposal, there was plenty to marvel at, from the kangaroo leather swatches patchworked together into a checkerboard of matte and shine to the kaleidoscopic application of holographic baubles on brocade. Only a house with the high-techiest technologies at its disposal could pull off that kind of embroidery.

During a post-show interview conducted on board the train, Jacobs said he was interested in "things looking like they were from another time." The exhibition Louis Vuitton—Marc Jacobs, opening at Les Arts Décoratifs tonight, which tells the tale of the two men's contributions to the megabrand, clearly had Jacobs thinking about the company's nineteenth-century origins and travel heritage—and how to make the synergistic most of them.

Fifteen years into his tenure at Vuitton, he's not just one of the world's most fanciful designers and extraordinary showmen, he's also a damn smart businessman.