Big Sal Condito had been standing under the high wire at the circus for 18 years, on and off, and nobody ever fell. But Sal remained vigilant. Suddenly it happened. A couple of months ago in Savannah a man skipping rope slipped from the wire.

When someone falls 42 feet from the high wire, the idea for the man on the ground is to rush underneath and break the fall anyway he can, preferably with his shoulder, Sal Condito, ouot of Newark, N.J., 51 years old and weighing about 230 pounds, can move fast when he has to. He's got the size and short-distance speed for the job. Condito got under the falling artist so fast that, as he put it yesterday, kind of offhandedly, "It was just a matter of waiting for him." At the Ringling Bros and Barnum & Bailey Circus, which opened last night at Capital Centre, one naturally looks up, to the "supreme daredevilry on the slender silver strand," as the circus press agents say, leaving Sal Condito a large, overlooked man below.

The job of catching a falling colleague is a grim and overlooked business, but like lots of daredevils the men in it speak of the dangers matter-of-factly.

"I nudged him," said Condito of the close call in Savannah."He landed on the mat. Makes you feel good."

Linwood "Big Red" Gardner, 35, ("Hardly anybody knows my name is Linwood") comes from "more or less California," has red hair, red bushy sideburns, a red mustache, and weighs 303 pounds (down from 320). Though he's bigger than Sal, he is similarly quick like Sal, and he has been under one almost-fatal fall.

"'Bout seven years ago," he said, standing next to some rigging at Capital Centre. "Raleigh, N.C., I had a girl on a trapeze. Her husband and I would spot the ring. He'd get the front half, I'd get the back half. She came down head first. I hit her, caught her, and set her down on the ground." He smiled.

As catchers of men, Sal and "Big Red" have earned a unique respect. "It's a special feeling you get in the business," says "Big Red," "knowing you can do something like that if you have to. No party, nothing like that. But people would come by, say hello, you know."

When things go wrong but turn out right, the catcher often gets the worst of it. Said "Red": "She bruised her heel. I pulled some ligaments in my leg and hurt my back."

Gerhard Richter looked as if he had been under a fall, but hadn't. He had his neck in a collar because of a pinched nerve from a little-known heroic moment, trying to pull some rigging together recently in Rhode Island. As Condito said, "Everything has to be perfect," and Richter is known for getting the rigging that way.

He came to the United States from Germany in 1968 with Gunther GebelWilliams, star tiger trainer as a handyman with the animals. Even now, he likes to make sure the chimps don't run away from their act; he can get them back merely by calling their names (except for the time he had to go up on a girder in Madison Square Garden after one).

Richter said he also is friendly with the elephants - even though he's been charged twice by them.

One was his old friend, Banana. This was in Florida and she stopped right away when he called her, at least briefly. She then turned ran off to a small airport and stopped at the edge of the runway. "An elephant only runs so far," said Richter. "Then it stops and asks what happened."

The other elephant charge happened so fast Richter rolls his eyes at the thought.

"I was going to this candy machine," he said. "I had just put the money in and pulled the pin when this elephant charged. I was lucky. I just had my hand in front of his paw. He kicked in the machine."

There were about 75 men putting up the circus yesterday under the supervision of Dean McMurray, the general manager, and his predecessor, "Tuffy" Genders, who is 67 and now a "consultant" who probably knows more than anybody around. He worked as a catcher in a flying trapeze act the first 15 years of his career. When he got to be "38ish," he said he had a chance to get "the front door job - that involved taking the tickets."

Genders played himself in Cecil B. DeMille's. "The Greatest Show on Earth." He said, "DeMille was a real stickler for authenticity. He said, 'Anybody can do it with piano wire. We want to really do it.' We stood Cornel Wilde on his head, literally."