The security guard slipped out his can of mace, but in the struggle he sprayed his partner’s face, the whole rear of the car, and at last his opponent.

On the San Diego Trolley, the decision to buy a ticket or not is up to you. It's called the honor system. When I first heard about the trolley in 1981, the implications of honor and trust delighted me, spoke of softer, more innocent times, of study halls and homework and cookies. Yet part of me thought that these people must be naive. If nobody is there to make me buy a ticket, what’s to stop me from taking a free ride just for the hell of it? Besides, the trains run through some rough areas, places where a person might resent forking over hard-earned cash to something so bright and modern and affluent-looking as this trolley system.

Yet the system does seem to work, though it’s not all based on honor. Chances are a roving ticket inspector will come aboard sometime during your trip. If you paid your fare, dropped quarters into a ticket machine before boarding, okay. If not, the inspector writes you a citation. Sounds simple. It isn’t always.

One night recently I saw ten rows of seats cleared by mace in a desperate struggle between a tall black man and a ticket inspector and her armed security guard escort. The man had no ticket and refused to show his ID, and when the train stopped at a station, he tried to run. The trolley agents restrained him. That’s a polite way of saying it. Fists hammered flesh. A guard’s baton rose and disappeared into the mess of sweating faces and heaving trolley uniforms.

The rest of us passengers stood transfixed. Glancing around, I saw fear and concern and distress, and I knew that most of us in the crowd felt the same thing: we were monkeys watching lions at work, caught in that awful two-way pull — disturbed by such violence over what, at most, amounted to a buck-fifty fare, and at the same time hating our own selfish relief that it wasn’t us being hammered on, that we were safe from predators, for the moment.

We stood in a strange silence. The wheels clicked on the tracks, and the knot of struggling bodies crashed against seats and banged into the walls of the trolley. But there was a muted quality to it all, as if we were caught in the silent movie of our own disbelief.

Finally the security guard slipped out his can of mace, but in the struggle he sprayed his partner’s face, the whole rear of the car, and at last his opponent. The trolley pulled into a South Bay station lit by the whirling lights of police cars. The last I saw of the black man, he was being slammed onto the hood of a two-tone car as we accelerated toward Tijuana. Then the silence in the train popped. People swore and chattered, waved their hands, anything to work off adrenaline. After a while, everyone took their seats, their wrinkled foreheads smoothed out, and the night flowed past the windows as if nothing had happened.

These scuffles “happen fairly often ” says Terri, the young woman driving the trolley that night. (Her name and those of her fellow trolley workers have been changed for this story.) Though she hates the occasional violence, she meets a diversity of people on the late runs and hopes they will enrich novels she will someday write.

And these night travelers are a diverse lot. One old guy looks like a retired cowboy with a tobacco-stained beard. He sucks his gums, checking out the women as they board, studying their rear ends as if they were paintings. But when any of these women take a seat and face him, they find him staring out a window — he’s that good.

A Hispanic man tells me he lives in Tijuana and commutes to a job and girlfriend in San Diego. He says his parents came from Spain and Portugal, but he has the square build and classic nose of an Aztec. A Mexican accent softens his speech, makes it more musical. I think of the old joke that goes. “I’m not Mexican, just French-Canadian,” as if being Mexican isn't good enough. Having grown up in Mexico, I recognize in him the curious mixture of pride and shame a Mexican feels about his roots. They are strong roots, colorful ones, but flawed by poverty and corruption. I smile at this man as he tells stories about all the dead people he’s seen.

The most entertaining passengers are the three guys flirting with Terri. Like tomcats, they crowd around the door to the little cabin where Terri operates the train. The old-timer, his gray hair like wings on the sides of his skull, likes to square-dance, though some nights he sings in a chorus. His friendliness has a nervous edge. The middle-aged commuter, with his slick hair and empty banter, is as cocky as a high school boy. He blocks the cabin door with his shoulders, which makes the youngest man brood. The brooder is Oriental, handsome in his Grateful Dead T-shirt. It bothers him when the other guys capture too much of Terri’s attention.

The way these guys stand, an easy balance with the sharp movements of the train, shows they’ve been at this courtship ritual for some time. When the commuter jumps off at his stop. Square-dancer replaces him at the cabin door. But when Square-dancer turns aside for an instant. Brooder slides in, and now he smiles. Later, Terri tells me they know she’s married, but it doesn't seem to matter to them.

Indeed, Terri is attractive. Though she’s pretty, her attraction comes as much from a willingness to laugh, an interest in people, and a way of listening that makes you feel comfortable. And she is extremely competent.

Earlier that evening. I had followed along as Terri began her shift. Her first few hours on the job were spent putting trains away for the night. By the start of her work day, at 5:30, the rush hour was winding down. As trains pulled into the station at Twelfth and Imperial downtown, Terri uncoupled spare cars and parked them on unused track in the main yard. Some trolleys she ran through a giant car wash, others into the maintenance shed. She made it look easy, driving trains and jumping on and off to throw the track switches in a relaxed way.

The switches control the direction a train takes when it comes to a fork in the track, and they’re heavy. Swinging the big levers up and slamming them down on the other side of the switching boxes actually slides a section of steel track, and when I tried one, it made me strain. I looked at Terri with new respect. My mother worked in a factory during World War II, and she is still proud of discovering that rhythm and balance make physical work easy. That’s what I thought of as I watched Terri work.

A music major in college, she sang madrigals and choir music while nurturing a secret desire to be in a rock group. But when she graduated from San Diego State, she took a job driving buses, and when the trolley system opened, she eagerly applied for the job of driving trains.

“I was always a closet rail fan,” Terri says. She visits other rail systems during vacations. She likes to see how they operate and to talk to the people who run them. There’s a kind of fraternity among people who drive trains. In fact, she says it's something you’ll see among drivers of “anything that moves.” Bus drivers flash headlights at each other. Taxi drivers toot their horns. Train operators wave.

And they are trains, these cute red trolleys. They may have an umbilical connection to an overhead power line in the same manner as streetcars, but they are still trains. They even share track with the San Diego-Imperial Valley Railroad. Their steel wheels are as thick as a child’s thigh and as tall as a security guard's gun belt.

Back on the trolley, Terri lounges in the driver’s seat. The train’s lights cut through the darkness, illuminating the gravel of the railbed and making shadows leap ahead of us. The tomcat guys have gone. We head north again, though Terri tells me no trains run north and south. In train language, north is called west and south is called east. It’s a tradition, she says, that comes from a time when most railways ran east and west.

A short distance “west" of San Ysidro, Terri points out embankments and gullies where she commonly sees illegal aliens.

According to her, when they use the train, they are better than most at having their tickets ready; the coyotes, smugglers who run the illegals across the border, generally buy tickets for their flock of pollos before setting them loose. She says there used to be more bushes close to the tracks, and when she pulled her train into southern stations on the north run, aliens would materialize out of the sagebrush. “They used to pop up like flowers,” she says. Now they lie flat on embankments or hide behind pillars or trashcans. Terri laughs. "They think we can’t see them."

At the Iris Avenue station, a couple of stops up from the end of the line, two border patrol agents prowl through the train with their sharp eyes, creaking leather, and handcuffs swinging from their belts. They don’t find any illegals to take off this time, but Terri says she has seen them make a sweep and practically empty the train.

I think about what a campesino must have gone through to get this far, about the forces that drive so many of them here, and about how bright and fast everything on this side must look. Maybe the trolley does more than connect downtown with the border. Maybe on another level it makes a run through the heart of dichotomy.

Downtown, where the tracks begin, glass skyscrapers and new art deco buildings shine light on people living out of shopping carts.

Farther south, the tracks cut through an edge of the barrio, where tough guys paint murals in a park beneath freeway ramps. Some time back, a body was found stuffed under a bench at the trolley station here.

Then there’s National City, a place so red-necked, so raunchy, it seems more like Texas than part of Southern California. Its cowboys and mean cops could be kicking ass in the same kind of bars a thousand miles inland.

Chula Vista’s irrigated lawns bring a touch of green to the desert, then comes San Ysidro. End of the line. There the fast-food joints and neon from Mexican insurance signs face the freeways. So the train arrives out of darkness. In that dark corridor is a nightly fluttering and scurrying of rabbits, owls, and frightened aliens looking out at a strange new life.

After the border patrol agents step off, the train is quiet, except for a loud group of drunken sailors. The seats face each other, and most passengers avoid eye contact by twisting sideways. As the trolley rolls north, litter drifts in the aisles.

Terri says she has found packets of marijuana, old food, even clothes left behind by passengers. She never has to buy a newspaper, and one time she “got a nice big bottle of tequila." The worst thing to find, though, is vomit left behind by the drunks. Terri grins and pats a compartment that contains a substance called "Oops,” a euphemism for the same sawdust stuff I remember grade-school custodians using when some kid barfed in the cafeteria.

At the Palm City station, a female ticket inspector and a male security guard swing aboard. They work the aisle with a cadence and rhythm like a kind of dance — rock with the train, dip to see the ticket, clutch that pole, shuffle to the next seat. When they reach the end of the train where I sit, I recognize them from the fight earlier.

“I could tell he was gonna rabbit,” the ticket inspector says of the man she and her partner fought. “He rabbited earlier, and I could see it coming again."

She is young, maybe twenty-five, short and tough with the softening touches of a coral necklace and tiny earrings. She stands with a certain macho quality, like a stationary swagger. Her partner, the guard, seems uncomfortable with my questions. He frowns, thumbs hooked in his gun belt.

But the inspector is glad to talk. She steps closer and my eyes begin to water. I realize she was maced so thoroughly that the stuff is still seeping out of her uniform. It doesn’t bother her, though, and in a controlled monotone she tells about letting the tall man get away the first time because the trolley system has a policy of not chasing fare cheaters. Something to do with PR. consciousness. When the guy got back on the train two hours later, he tried to “rabbit" again, but she figured letting him go would have been the same as telling the world that it’s okay to cheat and run.

I marvel at this small woman jumping a man twice her size. Her attitude may be six feel tall, but that doesn’t change simple physics. And then there’s that coral necklace and the slightest hint of vulnerability in her eyes. Nonetheless, she takes law enforcement seriously, and it worries her that the ticket inspectors can’t carry weapons. In her same controlled way, she describes the people she and her partner deal with on the late shifts: the drunks, the crazies, the molesters and flashers, the gangs and the thieves. While she talks, the guard shifts his weight and hitches his gun belt. Then the trolley stops at a station, and the pair jump off to inspect a train going in the opposite direction.

Later I talk with Anita, another ticket inspector. She, too, is short and tough. Her softening touch is a smile. Though she says, “Oh, we’ve had some real battles,’’ she sees policing the train as more of a game, a kind of forejumper’s tag. When she does tag someone, they pay a $46 fine. The second time costs $86, and the third time costs $500 and/or six months in jail. Part of the game is the excuses people give for not having a ticket. She laughs and says she has heard every excuse known to mankind. When she hears an especially good one, she figures, “If they went to all that trouble, I usually let them off with a warning.”

But Anita gets serious when she says the trolley's honor system is important. The way she views the ethical climate, the system could be like a small brick in the rebuilding of America’s moral foundation. She says. "If you can get something like this started, it’s good for the country.’’ She remembers simpler times, when trust was a more common thing. But her assessment of humanity is that ninety percent of us are pretty decent folk. It’s the other ten percent who "just don’t care "

On my last ride that night. I wonder if the trolleys are something I would use. and I decide, yes. if they went someplace I wanted to go. indeed I would use them. They are comfortable and quick, they come often, and they don’t cost too much. The system works. In Southern California, where good public transportation has been as rare as a snow tire, that’s saying something.

I look down the aisle at a group of Hispanic men sharing nips from a bottle in a brown bag. at the black family with the little girl asleep on her father’s shoulder, at the ubiquitous loud sailors, the old woman chewing her gums, and the quiet gray people who sit alone and meet nobody’s gaze. I get a feeling I’ve never had in an automobile. I’m part of a bigger thing, humanity. I can’t help it, I think of us as a kind of pudding, tapioca, and if ten percent of the tapioca beads are flawed. I don't mind.

I realize the night is working on me. bringing out my sentimentality. Time to go home. On the dark street downtown where I parked my car. an old bum shuffles by talking to himself. I stop to listen. Over and over, he chants.

"Loco, loco, loco."