Not every city is suited for a light-rail mass transit system. Even the most zealous of rail transit advocates is willing to admit that.

But not every city is St. Louis.This city's unique urban landscape has set the stage for what has been one of the recent success stories in modern U.S. light-rail transit - if, that is, success can be measured by the number of people who ride MetroLink trains every day (about 46,000).

If the towering Arch on the Mississippi river front is the Gateway to the West, then MetroLink is the gateway to St. Louis.

The 17-mile line stretches from Lambert-St. Louis International Airport to the University of Missouri-St. Louis, past three professional sports arenas to the city's convention center, to the deck of two riverboat casinos and on across the Mississippi to East St. Louis, Ill., and one of the largest light-rail park-and-ride lots in the country (nearly 1,000 spaces).

It picks up business travelers at the airport and drops them off near their hotels. It takes commuters out of their cars and into the city. It takes downtown workers to their favorite lunchtime restaurants for free. It saves St. Louis Rams, Blues and Cardinals fans from having to pay $10-$20 to park near the three downtown stadiums.

At rush hour, MetroLink cars are packed and often limited to standing-room only. The noontime hours are busy, too, and airline passengers with their luggage in tow are a common site at any hour.

"It just doesn't make sense to drive downtown and pay $20 to park," said Dave Holland, a construction engineer who drives from an Illinois suburb to the East St. Louis park-and-ride lot and hops MetroLink across the river for the last eight minutes of his daily commute.

"They said nobody would park in East St. Louis with all the crime and drugs over there, but they were wrong. It's a secure lot. I drive a BMW, and I wouldn't leave it there if I thought it wasn't safe."

During weekday morning and afternoon peak periods, the two-car MetroLink trains run every seven minutes. The rest of the day and on Saturdays and Sundays, they depart each of the system's 17 stations every 10 minutes. In the evenings, seven days a week, trains run every 15 minutes. They run more frequently before and after sporting events.

Few riders bother to check a schedule. No matter when they get to a station, they know a train will arrive soon. MetroLink officials say their trains are on time 99 percent of the time.

The stations, even the three downtown tunnel stops, are relatively clean and crime-free. MetroLink security officers make their presence known but are not so numerous as to provoke police-state images like the systems in San Diego and Los Angeles.

The cars run smoothly and quietly enough to encourage conversation. It's even possible to stand up without holding onto a support.

And people of different cultures and classes, from all walks of life, ride the rails together.

"I was struck by the fact that it is truly a white-collar form of transportation," said Sandy Mayor Tom Dolan, who previously toured the MetroLink system and rode it again last week as part of a visiting Utah delegation. "In Utah, I don't see a lot of white-collar people riding the bus, although obviously they do. I think, for whatever cultural reasons, a bus doesn't have the same feeling as light rail.

"(Light rail) is cleaner, faster, more upscale. The businessman who would be commuting to and from a job feels more comfortable riding light rail than a bus system."

Five members of the Utah Transit Authority and other Utahns joined Dolan in attending the Rail-Volution transit and community development conference at the city's historic Union Station. More than a dozen of them spent Tuesday afternoon touring MetroLink's facilities.

"It seemed to work quite well," Kevin Young, a transportation engineer for Salt Lake City, said of MetroLink. "It's just very efficient, right on time."

Plenty of St. Louisans weren't convinced a modern trolley car would work in the 1990s. From the time the Bi-State Development Agency began considering light rail in the early 1980s until MetroLink opened in July 1993, many here doubted light rail would do anything except lighten taxpayers' wallets.

Even MetroLink forecasters thought only 12,000 passengers would ride the system each weekday. But actual ridership was 24,000 a day in the first month of operation. By 1995, ridership was in the 37,000 range and now exceeds 45,000 most weekdays.

In its four-plus years of existence, MetroLink has been one of the safest U.S. light-rail systems with only two injury-causing accidents that drew much attention. One involved an intoxicated man who stumbled onto the tracks and was hit but not seriously hurt. The Los Angeles blue line, in contrast, has been responsible for 30 deaths in seven years.

The safety record of any light-rail system, however, is directly linked to the number of times trains cross surface streets. In many cities, light rail operates primarily in the center of roadways, as it will for the downtown Salt Lake City segment of UTA's Transit Express (TRAX), now under construction.

UTA was fortunate to have acquired an existing rail corridor for its initial 15-mile light-rail line from Sandy to Salt Lake City. The agency had to battle, however, for permission to place tracks down the center of Salt Lake City's Main Street.

UTA might have another struggle on its hands with a proposed 10.9-mile light-rail extension from Salt Lake International Airport to the University of Utah. The difficulty, in this case, is coming up with $374 million to build the extension, not to mention the added operating costs. The UTA board supports continued planning of the extension, but board member Richard Kuchinsky says the project is essentially "on the shelf" without funding.

UTA General Manager John Inglish, who spoke at the conference Tuesday, believes any tax increase for expanded light rail won't get voter approval until after the initial line is up and running - that's March 2000 at the earliest. But Salt Lake City Mayor Deedee Corradini is hoping to have the airport-to-university line completed in time for the 2002 Winter Olympics.

Salt Lake International is just an eight mile drive from Temple Square. It is among the largest generators of vehicle traffic in Utah, along with downtown Salt Lake City and the university.

A light-rail connection would increase an airline passenger's options, giving those with a brief layover a chance to visit downtown - and leave a few dollars behind. Light rail at the airport might encourage return visits or even prompt business relocations, some observers say.

There is still public skepticism about light rail in the Salt Lake Valley, and political opposition to any tax increase to fund it. Like their counterparts in St. Louis, UTA and the regional planners who promote light rail may have to lay low until TRAX is in place, then let the groundswell of public support they anticipate carry them into the next phase of light-rail development.