BARGE TRIPS The Canal Clipper runs Fridays, Saturdays and Sundays until June 1, when it will run Tuesdays through Saturdays. Departure times from Great Falls, Maryland, are 11:30, 1:30, 3:30 and 5:30. Tickets, at $2.15 for adults and $1.05 for children under 12, can be bought up to two hours before departure. Charter trips are available. Details: 229-2026.

The C&O Canal is so jammed with trendy joggers these days it's hard to remember that well into this century it was a place of work. From its opening in 1850 until it was superseded by the railroads in 1923, the 184-mile waterway was the province of the "canal rats" - the men, women and children who spent their lives on barges, lugging supplies each week from the wild Cumberland country to the city folks in Georgetown.

For the past three years, in an effort to recreate that rough-and-tumble world, the National Park Service has taken passengers on barge rides down the canal. This season, repair work at the Georgetown end of the canal has forced the relocation of the trip upstream to the Great Falls area, and it's just as well: The park rangers say the quieter, relaxed ride is most appropriate to the 19th-century mood anyway.

At the beginning of a recent barge trip, it was anything but quiet as four young Park Service employees, dressed in late-19th-century costumes, untied the barge and pushed us away from the dock. The trip begins with an eight-foot ascent in one of the canal's few working locks - "Just think of it as an old-fashioned elevator," crew member Roger Abramson, 25, tells the passengers - and getting the barge into the lock requires a considerable amount of pushing, prodding and yelling back and forth among the crew. Finally the lock gate is slammed shut, water rushes in and the Canal Clipper, a 30-ton, 87-foot replica of the early barges, begins to rise. Twenty mintues later we're up at eye level with the runners, bikers and picnickers who've lined up along the path to watch our progress.

As the mules start to tow us down the path, Abramson, Jessica Giusti, Julie Shorter and Jon Singleton take their places around the barge and start a spirited dialogue, complete with country accents and backwoods jargon. "Why we had a mule once that pulled like nothin' you ever seen," Shorter tells one little girl who's commented on the docility of the "horses" towing us. As the crew members talk of muleskinning and jackrabbit stew and catfish suppers, a picture of canal life begins to take shape. The children are content to sit back and listen. The adults ask about the general routine of barge life, but basically it's a quiet, peaceful cruise as everyone revels in the stillness of the canal.

Most of the kids on board are five and under - too young to appreciate the historical aspect of the ride, says park employee Jim Branslow. "They think of it as an amusement type of ride. That definitely plays a part, but we want to show what life was like on the canal." The program is designed for 10-year-olds and up.

Gliding down the canal, listening to the lapping sound of the water against the side of the barge, it's easy to get caught up in the romance of it all. But the crew members don't want us to forget that it was not a cushy life. When a boy comments that the kids who led the mules down the path had a "neat" job, he's told that they only made $10 a month - "and even back then that wasn't anything great."

The tempo picks up a bit when the crew members break the fiddles out and play a few tunes from the 1860 hit parade. Soon they've got everyone joining in innumerable choruses of "O Susannah." A song celebrating the qualities of groundhog meat is a big hit with ASHLEY HADLEY, FIVE, AND HER NINE-YEAR-OLD BROTHER, WILL, AND THEY SING ALONG WITH THE REST OF THE KIDS ON BOARD UNTIL SUDDENLY THE BARGE IS BACK AT LOCK 20. EVERYBODY'S VERY ALERT AS THE CREW GETS THE BARGE INTO POSITION FOR ITS EIGHT-FOOT DESCENT. "WE'RE GONNA SINK! WE'RE GONNA SINK!" ASHLEY SHRIEKS WITH DELIGHT. THEN HER ATTENTION WANDERS AS SHE SPIES SOME MALLARDS AND OTHER DUCKS SWIMMING ON THE CANAL. "CAN WE GO FEED THE SWANS NEXT?" SHE ASKS. CAPTION: Picture, A LIESURELY TOW THROUGH THE PAST. By K. C. Summers.