A century of ups & downs on Coney Is.

Boardwalk's a landmark now- and it's better than ever

CONEY Island, baby!

More than 40 years since Lou Reed’s most romantic album, it’s a pity the rocker isn’t around to see the changes along the city’s iconic ocean beach and boardwalk.

It’s been a long, strange, rollercoaster ride for Coney Island since Fred Trump, President Trump’s dad, gleefully demolished Steeplechase Park in 1966 — the last of the boardwalk’s trio of great amusement parks.

Fred, who wanted to build “Miami Beach-style” apartments, leveled Steeplechase before the city could declare it a landmark. So it’s delicious irony that the Landmarks Preservation Commission this month designated the 2.4-mile-long boardwalk an official “scenic landmark,” meaning it can’t be altered without city approval.

The officially named Riegelmann Boardwalk, as the seaside promenade is called by no one, is on a roll from end-to-end.

Memorial Day weekend will see the opening of a new Luna Park thrill ride, Astro Tower, a 137-foot-tall scream machine that treats riders to “dramatic freefall drops and rotation.” Two more “family-friendly” rides will follow in coming weeks.

The fabled Coney Island of 100 years ago can’t return. The larger neighborhood of 50,000 mostly low-income residents remains tense and troubled.

But the smarter comparison is between the beachfront’s seemingly irreversible decline of the 1970s-’90s and its rejuvenated current state — a heart-lifting story of New York’s regenerative powers.

THE boardwalk, originally constructed in 1923, is the safest it’s been in generations. Steeplechase Pier, which juts 1,100 feet into the Atlantic, was rebuilt after Hurricane Sandy with shade canopies and a raised viewing platform. The Ford Amphitheater and an indoor-outdoor eatery brought the decades-vacant former Childs Restaurant building back to life last year.

A full-length boardwalk stroll offers an unrivaled urban spectacle of sky, sea and sand. (Be advised, there’s virtually no shade.) Its gracious width varies between 50 and 80 feet, according to the Department of Parks & Recreation — broader than most boulevards. More than 170 castiron, twin-fixture light poles lend a handsome grace note.

The boardwalk’s intense heart is the amusement zone near the Stillwell Avenue subway terminal, but it’s rewarding everywhere. The only constant is the ocean, where swimmers’ squeals mingle with cries of wheeling gulls.

Lonely and teeming by turns, the boardwalk brushes shoulders with the private Sea Gate enclave, the New York Aquarium, where a new $146 million exhibition — Ocean Wonders: Sharks! — opens June 30, and open-air Russian cafes in Brighton Beach, where a gut-busting, four-course lunch is all of $19.95.

The boardwalk’s colorful, polyglot life today is a far cry from the years when it was largely abandoned by the middle class, and crime, decay and abandonment reigned. The Parachute Jump’s rusted hulk towered over empty lots like the totem of an ancient civilization.

“In its heyday at the turn of the previous century, Coney Island was the ultimate example of individualism and ingenuity. What’s remarkable is its survival instinct,” says Stephen M. Silverman, author of “The Amusement Park: 900 Years of Spills & Thrills,” due out from Hachette next spring.

Silverman noted that Coney Island suffered “from fires, one after the other. Then from the ravages of the Depression, followed by almost unrivaled urban decay. Now, it’s a great place to catch a ball game, dip into the past on the Cyclone and Wonder Wheel, and experience a polyglot experience steeped in American tradition. And I’m not just talking hot dogs.”

CONEY Island in the early 20th century boasted three distinct amusement parks: Luna Park, Steeplechase Park and Dreamland.

Luna Park alone glowed under 250,000 electric lights. Visitors enjoyed primitive, Las Vegas-style spectacles like rides to the moon, an entire “midget city” and fields of free-roaming wild animals.

The golden era, or the idea of it, has a mythic hold on the New York imagination. In Woody Allen’s “Annie Hall,” Alvy Singer recalls growing up under a Coney Island roller coaster. There really was a house under the original Thunderbolt, which closed in 1982 and stood fenced and forlorn until it was demolished in 2000.

The peninsula inspired poet Lawrence Ferlinghetti’s “A Coney Island of the Mind,” as well as “Coney Island Troubadour,” Woody Guthrie’s odes to Mermaid Avenue, where he once lived (“where the lox and bagels meet . . . where the beer flows to the ocean/where the wine runs to the sea”).

But darkness, too, lurked behind the shimmering lights. The Spanish writer Federico García Lorca’s posthumous 1940 collection, “The Poet in New York,” included a cheerfully dystopian work, “Landscape of a Vomiting Multitude (Dusk at Coney Island).”

The surreal weirdness extended beyond freak shows fea- turing human oddities like “FourLegged Girl” Josephine Myrtle Corbin, who also reputedly had two pelvises and two vaginas.

Violence-prone Topsy the Elephant was executed by electricity at Luna Park on Jan. 4, 1903. The poor creature was fitted with copper-lined sandals and fried to death in front of thousands of reporters and spectators, some of whom paid to watch from rooftops.

Grainy film of the sickening spectacle survives on YouTube. But no image exists of Coney Island’s most notorious demise.

FBI snitch Abe Reles was to testify against mobster Albert Anastasia. To keep Reles safe, he was guarded by a platoon of cops on the sixth floor of the Half Moon Hotel on the boardwalk at West 29th Street. But on Nov. 12, 1941, Reles either jumped or was pushed out the window — inspiring the famous line, “This canary could sing, but couldn’t fly.”

Coney Island started losing its juice after World War II. “Master builder” Robert Moses, to drive fun-seekers to his new Long Island beach parks via his new highways, promoted construction of low-income housing behind the boardwalk.

Two parks, Luna Park and Dreamland, closed. But it was left

to developer Fred Trump to administer the near-fatal blow.

He secretly bought Steeplechase from its money-losing owners and held a “demolition party.” As Politico describes it, “On a rainy Sept. 21, 1966, as models in bikinis posed for pictures in the oversized shovel of a bulldozer, a grinning Trump held an ax and prodded his guests to whip bricks through the signature stained glass ‘funny face’ on the facade of the park’s pavilion.”

Later that night, he bulldozed what remained to the ground.

Trump never got city approval to build apartments and sold the land. Coney Island soon tail- spinned into chaos along with the rest of the city.

BUT a handful of “pillars” had just enough appeal to get Coney Island through the grim years, says George Shea, the host and a producer of the annual Nathan’s July 4th hotdog-eating contest.

The Wonder Wheel, the Cyclone, 100-year-old Italian restaurant Gargiulo’s and Nathan’s Famous “were the spine that still drew people,” he said.

When Shea first got involved with competitive hot-dog-eating in the 1980s, “there were lots of homeless people all around, it was a very gritty scene.”

Things started looking up when then-Mayor Rudy Giuliani dispatched the NYPD to restore order to the boardwalk. Not only the muggers were curbed — in 1998, I watched cops order a 30foot-long snake back into its owner’s very large container.

Giuliani also brought baseball’s minor-league Brooklyn Cyclones to a new stadium. Even so, some of the creepy old spirit endured in the new millennium.

Shea recalls a ghastly “attraction” that opened in 2000 called Shoot the Freak — Live Human Target. “There was an empty lot between two buildings behind the boardwalk, like a gap tooth filled with rubble and cement,” Shea said. “In that area was a guy with a mask on and a horror outfit. He’d run around and you shot him with a paintball for $5.”

It made violence seem like fun just 10 years after the city suffered a record 2,245 murders.

Shoot the Freak got the boot in 2010, when then-Mayor Mike Bloomberg lured Italian amusement-park designer Zamperla to launch a new Luna Park and also to operate the Cyclone next door.

More thrills followed. A new Thunderbolt’s 115-foot vertical drop, 1,000-foot-long vertical loop and 80-foot-long zero-grav- ity roll made a Cyclone ride seem as smooth to some riders as an airport people-mover, although some still prefer the rickety wooden classic.

Mayor de Blasio is trying to expand the amusement area even more. Wholesome tastes of the long-ago Coney can still be found at Tom’s Coney Island cafe, on the boardwalk since 1936, and William’s Candy, Shop, which has been on Surf Avenue for more than 75 years.

But best of all, the boardwalk is safe forever — if not from another Sandy, at least from any future Fred Trump.