Spend Saturday night on the subway, they said. Find out where people are going and why they're going there. And make sure that something happens. If you need to get mugged to get a story, get mugged.

Those were, more or less, the instructions. Here is what did not happen:

"It was late. As the train pulled into Washington Street Station, the wino clutched the neck of his brown paper bag and lurched through the door. I realized with a quick chill that I was alone, totally alone. Suddenly, as the doors slid shut, a trio of leather-jacketed, acne-scarred youth darted onto the train. The stench of beer and sweat and corruption filled my nostrils. As one of the toughs sprawled insolently across a seat, another flicked his switchblade open and shut in dull, menacing repetition.

"Then he noticed me..."

No muggings, no hijacks, no escaped lunatics. But the Boston subway as Saturday evening entertainment turned out to have its advantages: cheaper than a drive-in, warmer than ice-skating, and more conducive to intimate discussion than a freshman mixer.

At the Harvard Square station, David Hershey-Webb ("pretentious name," he apologized) told me has cut short a planned evening of guitar-playing, singing and coin-collecting in front of the Coop to go to a party at the Commonwealth School, a progressive private school in a Back Bay townhouse. "I went to school there last year, and I'm going to go there again next year," Hershey-Webb said. "This year I'm taking a sabbatical at a Boston public high school so I won't be a private schoolie like her." He pointed to the girl sitting next to him. She did not smile or seem insulted, but acknowledged that she went to Commonwealth and said that her name was Deborah Alkema. Like Hershey-Webb, she had long blond hair and wore jeans but unlike him she sported no Udall button.

Hershey-Webb went on. "The school I'm at now is really terrible. It blew my mind. There are seniors who can't read. If you can't read, you're nowhere. What they do all day is beat people up." Hershey-Webb said he was "trying to reform the place in my own quiet way." So far his campaign had involved writing a letter to the school paper, explaining why "their methods of teaching are wrong, and their attitudes are wrong." "Anyway," he said, "it's an experience, and that's what I wanted." He and his friend got off on the right side of the train at Park Square, and I got off on the left.

At Park Square, a woman was waiting for an Ashmont car with what looked like a stewardess outfit folded neatly over her arm. She said her name was Pat and she was not a stewardess, but a guard for American Airlines. The insignia on her uniform said SECURITY '76.

For the last 16 months Pat had watched boarding passengers walk through the X-ray machines. She liked the job, she said, because there was always something going on and interesting people to see through. Just a few weeks ago, she said, Cliff Robertson had been at Logan. When pressed for an evaluation of Robertson's sex appeal, Pat admitted that only her sister had seen him, and that she hadn't even known who Robertson was. "But a while before that, one of Ford's sons came by," Pat said. "He walked through the machine like everyone else, even though he didn't have to."

Pat craned her neck as a train approached, but it was the wrong one. "Lord, I hate the subway," she said.

Upstairs the platform was almost empty. A uniformed T worker with a bullhorn had just announced to a small band, including a forlorn David Hershey-Webb, that a derailment at Copley Square had broken all Green Line service as far as Kenmore. Above ground, a confused crowd waited for buses. The overland route brought us to Kenmore Square, where another disgruntled crowd milled about. Across Beacon Street, in the Relax-A-Bit coffee house, a streetcar driver sullenly sipped coffee. He looked as gloomy as if he had driven the streetcar off its track himself; perhaps the derailment meant he would have to work late.

I took the stool next to him at the counter and greeted him.

"How'd it happen?" I asked cheerfully.

The man didn't look up from his coffee. "Don't know. Just got on duty now."

"Ahhh. That's what he says," a strange voice said.