This column last visited the High Line in March 2004. At that time, an uncertain fate awaited the elevated railroad structure on the West Side. Since then, the Friends of the High Line have prevented the structure’s demolition, and presented a plan for its transformation into an avant-garde elevated garden snaking through a theme park of chi-chi 21st-century architecture.

The High Line emerged in the 1930s as part of Robert Moses’s West Side Improvement, which also gave us a doubling of Riverside Park, the Henry Hudson Parkway, and the Miller Highway. Before the High Line, the New York Central’s waterside tracks ran at grade south from the yards around 34th Street. The trains served freight and factory facilities up and down the Hudson riverfront, a world-class hub of waterborne commerce until after World War II. Elevating the tracks eased traffic problems. The structure intricately weaves its way among and sometimes right through the old industrial buildings.

The High Line carried its last train in 1980. Since then the structure has loomed rustily over the far West Side. As happened with the passenger Els, property owners wanted the blighting structure demolished. The Friends of the High Line formed to preserve the structure and convert it into a park. The Bloomberg administration supports that idea, and by now so does just about everyone. The park idea comes from Paris: The Promenade Plantée, in the 12th Arrondissement, occupies a railroad viaduct that once served the Paris-Strasbourg line.

The Friends of the High Line has commissioned architects Field Operations and Diller Scofidio + Renfro and the landscape gardener Piet Oudolf to design the park. They have devised a preliminary plan, between Gansevoort and 15th Street, which may be viewed at the thehighline.org, and is scheduled to open next year. At first I regretted that the High Line had been preserved only to be made the plaything of architectural fashionistas. But the pictures of Mr. Oudolf’s gardens have won me over. The Dutchman has already graced New York with his Gardens of Remembrance at Battery Park.

A walk alongside the High Line shows a city in transition, gritty remnants of the industrial past commingling with some of the most fashionable establishments in Manhattan. The park will save an icon of the old waterfront, while at the same time ensuring that its surroundings, already getting chicer by the minute, become the trendiest, glitziest, and probably the most expensive part of the city.

In the west 20s, the High Line serves as a portal to the Chelsea gallery district. Walk south on Tenth Avenue, where the High Line looms just to your right.

At 19th Street, take a right to Eleventh Avenue to view Frank Gehry’s new building for Barry Diller’s InterActive Corporation. This is the perfect spot in town for a building by Gehry, and the perfect Gehry building for this spot. Billowing like a white sail — trafficking in that literalism that’s all that’s left when we’ve jettisoned the traditional languages of design — on the waterfront, the building does not fight with its surroundings. One wonders, though, if such buildings will have the same impact when their surroundings yield to scores of other aggressively chic buildings. For now, the Gehry building is certainly worth the detour.

At 88 Tenth Ave., between 15th and 16th streets, the restaurant Morimoto occupies a space designed for it by the famous Japanese architect, Tadao Ando. (Across the street, Mario Batali’s Del Posto and Tom Colicchio’s Craftsteak further remind us that this is the hottest restaurant neighborhood in Manhattan.) Chelsea Market, which houses Morimoto, occupies the block bounded by Ninth and Tenth avenues and 15th and 16th streets. The Nabisco factory rose in stages on this and nearby sites beginning in the 1890s. The main structure dates mostly from 1913 (the year after the invention of Oreos), and was altered in 1932 when the High Line arrived to service this, one of the largest factories along the route. Nabisco left in 1958. In recent years, developer Irwin Cohen has magically remade the building into a multiuse facility with, among other things, TV studios and, on the ground floor, a magnificent through-block food hall designed by Jeff Vandeberg.

Many New Yorkers recall Gansevoort Street solely as the meatpacking center, a place where carcasses hung from hooks, blood ran along curbs, and a stench permeated the air. It’s hard for some to get used to the new market, where the likes of Jeffrey (14th Street between Ninth and Tenth avenues), the trendy clothing store, crowd the meat places.

We’ve seen old industrial neighborhoods become chic and expensive. Here things are a bit different. The northward push of the fashionable West Village, the relocation of galleries to the West 20s, and finally the High Line park bring together three forces that each in itself would transform an area. What’s more, it’s a rare instance where most of the blocks aren’t of landmark quality, meaning lots of new buildings will go up, and the neighborhood will be made of new buildings — and one old railroad viaduct.

fmorrone@nysun.com