After nearly four decades of hanging around at the Embarcadero BART Station, waving at incoming and outgoing trains, a grimy character so familiar it eventually blended into the walls is retiring.

"Legs," the 50-foot-tall, 7,000-pound rope sculpture that has hung on the east wall of the station since it opened in 1976, will be carefully dismantled, removed from the station and returned to its creator, noted textile artist Barbara Shawcroft, 84, who lives in Davis.

The decommissioning of the public artwork is scheduled to start Friday when BART crews will erect scaffolding. Early next week, workers will dismantle the sculpture using detailed instructions prepared by the artist. By the end of the month, "Legs" will be part of BART's past, much like grungy brown upholstered seats and free parking.

There's some debate over whether the sculpture was installed in 1976 or 1978, but it was commissioned at a time when macrame and burnt orange were popular. While it may have had the appearance of oversized macrame, Shawcroft, a professor emeritus of the UC Davis School of Design, has said it's a Neolithic technique known as knotless netting.

"Legs" hangs through all three levels of the station, and is made of Nomex, a fireproof material. When it was installed, it was a rich orange and white, and it shimmied and swayed when trains sped in and out of the Transbay Tube.

"For me, this piece beautifully represents the time in which it was created," said Molly McArthur, a BART community relations representative who works on public art. "This is the '70s - it was perfect for its time."

But time and grime - particularly the dust from train brakes - took their toll on the sculpture, leaving it so dark and soiled it was scarcely noticeable against the station's gray walls. Over the years, Shawcroft tangled with BART officials who wanted it removed. In 1987, then-Director John Glenn likened it to a "hanging dish towel."

The artist insisted that BART should leave "Legs" dangling and said the agency's contract with her required them to clean the sculpture, something that proved costly and short-lived during three attempts. The standoff led to decades of inaction, with the sculpture seemingly forgotten.

BART budget proceedings last year brought the beginning of the end. The transit system included $300,000 in its budget for the removal of the artwork. Shawcroft initially contested the effort but eventually agreed to work with BART on the decommissioning. She could not be reached for comment for this story.

McArthur said she has worked with Shawcroft and that the artist understands that the grimy environs of a busy subway station aren't the best location for textile art.

"She's actually relieved it's going to be coming out of this environment," McArthur said.

Under the artist's agreement with BART, the sculpture will be removed in pieces, wrapped in plastic and delivered to Shawcroft. BART officials and the artist had looked for a museum to take in "Legs," but its size and condition made the search difficult. The artist is probably going to "repurpose" the sculpture into smaller pieces, she said.

"She is the creator of the work, and her heart still beats for it," McArthur said.

Once "Legs" is gone, all that will remain are memories and photographs. BART doesn't plan to replace the artwork, instead leaving the eastern wall of the station barren so it can be used for maintenance access - and to collect dust.

Michael Cabanatuan is a San Francisco Chronicle staff writer. E-mail: mcabanatuan@sfchronicle.com Twitter: @ctuan