New ups and downs for roller coaster buffs

When Chicagoan John Page says he still has a few worlds left to conquer, he's not talking about business ventures or distant travels. His eye is on those roller coasters he has not yet managed to ride.

Riding coasters is for him, as it is for most of the more than 1,000 other members of the Chicago-based American Coaster Enthusiasts (ACE), an almost all-consuming hobby. So far Mr. Page and his wife (''she married into it'') have climbed aboard about 50 of the estimated 250 roller coasters remaining in the United States.

At one time there were more than 2,000 roller coasters scattered among various amusement parks in this country. All had their roots in wood-supported ice slides built on Russian hillsides many decades ago, and they took some of their improvements from American trains. But during the depression of the 1930s, many were razed or shut down for economic reasons.

There are signs now that a coaster revival of sorts may be under way.

Several parks, including Riverside in Massachusetts and Kings Dominion in Virginia, are putting in new coasters. And in 1984, Kings Island near Cincinnati , which in 1972 built the first wooden roller coaster in the US in many years, will install an imported Japanese steel coaster that will carry riders standing up rather than sitting down.

Members of six-year-old ACE applaud every one of these new coaster arrivals, even as they work hard to ward off the demolition of existing coasters. When a preservation group in San Diego asked ACE's help to save a threatened coaster there, club members rallied with a burst of supportive letters to City Council members. The council ultimately decided to rebuild the coaster.

Although ACE member John Page insists there is no such thing as a ''bad'' coaster (''some are just better than others''), club members tend to agree on favorites. ''The Cyclone'' at Astroworld outside Houston, the record-holding 7, 400-foot-long ''Beast'' at Kings Island, and ''The Mind Bender'' at Six Flags Over Georgia all rank near the top.

Most ACE members also prefer wooden to steel coasters. Steel structures are cheaper and more easily mass-produced and maintained. They also tend to have more dramatic corkscrews and loops. But coaster enthusiasts say steel coaster turns tend to be more abrupt and the ride lacks variety. Wooden structures, by contrast, are built for the particular park site, are noisier, look more rickety (definitely part of the thrill), and offer a ride that varies according to weather and time of day.

''It's a more 'givey' kind of ride,'' insists ACE president Liucija Ambrosini. ''Loops aren't that interesting to me. The hills and turns are the exciting part.''

''Sometimes younger children and teen-agers are attracted to steel because of the gyrations,'' notes her husband, Allen, also an ACE member. ''But it's usually a shorter ride, and those visual things wear thin after a while. It's not the kind of ride you'd want to do over and over again.''

When ACE members gather for their annual convention or their more frequent regional meetings, repeat coaster rides at a nearby park are always on the agenda. In swapping experiences, members often illustrate with slides and photos , preferably shot from a coaster's front seat. Mr. Page, for instance, papers his den with blown up photos of favorite coasters and decorates his office cubicle with smaller pictures. Some members interested in engineering build coaster models. The club, which sells buttons, jackets, and T-shirts to stay financially afloat, has recently published its first book. It is about Harry G. Travers, who built some of the most unusual and curviest track in coaster history.

Hollywood's making of the film ''Roller Coaster'' a few years ago served as an impetus for the start of ACE. Some of the filming took place at Virginia's Kings Dominion, where a follow-up riders' marathon was held. Those taking part decided to get together the following year, and the club was launched.

In a recent newsletter, issued three times a year by ACE, members shared their innermost thoughts on coaster feats completed and hoped for. One member, for instance, lists all 50 coasters he rode in one brief six-month period. Another member from Ohio, one of the most richly endowed coaster states, says he has completed 2,400 rides and won't ''retire'' from coasting until he makes it 10,000.

Whether a coaster enthusiast rides in the front or the back of the train depends on his preference for experiencing the full force of the drops (better in back) or faster upward speeds (better in front). Like most ordinary tourists, they often ride with arms held high (lap bars hold them in place) and frequently''whoop and holler,'' says Allen Ambrosini.

''The difference with us is that the noise is generally from joy, not fright.''

Still, few ACE members would urge reluctant children or adults to take a coaster ride if they are not so inclined. John Page recalls that when his sister took him on his first ride at age 8, ''I couldn't wait.''

''It's good to start when you're young, but the best way to turn anybody off coasters is to force him to get on.''