CARY, Ill. (AP) _ The wail of ambulances was the first signal that Wednesday's lesson at Cary-Grove High School would be about tragedy.

Through rumors, whispers and a voice on an intercom, students learned that a commuter train had torn into a bus full of their classmates.

For a few frantic hours, the students and their parents were consumed by one question: Who had lived and who had died? The answer finally came _ four boys and a girl _ most not yet old enough to drive or stay out all night.

``We all know these kids, we all know whose kids they are,'' said Deborah Zopp, whose 16-year-old son, Stephan, attends the high school. ``We all feel their pain.''

The morning started out crisp and calm in Cary and neighboring Fox River Grove, towns that got their start as rural whistlestops and are slowly being engulfed by the suburban sprawl of Chicago, nearly 40 miles away.

When the first hint of the horror on the railroad tracks reached Cary-Grove High, 15-year-old sophomore Justin Borawski thought it was a joke.

``One kid came in five minutes late and said, `Oh yeah, there was an accident, can I get off the tardy?' And the teacher said, `Oh, yeah, I've heard that one before.'''

Senior Greg Hoffman saw three ambulances on his way to school and heard one after another as he sat in class. A school official finally appeared at the door and quietly summoned the teacher, who broke the news. A loudspeaker announcement followed.

``Everyone just went crazy,'' Hoffman said. ``They were in a state of shock.''

Weeping teens trudged from one classroom to another while school officials tried to determine who had been on the bus. Other students wandered the halls or gathered at the school library and the cafeteria, where counselors were on hand.

Eventually a partial list was posted with names of the injured and students who were safe.

Freshman Jill Anderson, 15, scanned the list feverishly, failing to find the name of a friend, realizing what it meant if someone was neither injured nor OK.

``You don't know what's the truth,'' she said.

Zopp was at work when she had a frantic phone conversation about the accident with a friend. She decided the crash likely had happened after her son's bus reached school, and then she got another call. It was Stephan.

``He goes, `Hi, Mom. It wasn't me,''' she said, standing outside the high school.

Officially, the dead were nameless until late afternoon, after next-of-kin had been notified. But around the school, the tearful students and their grim-faced parents knew.

Stephan Zopp knew three of the dead boys, and two were longtime friends, his mother said.

Jeff Clark went to elementary school with Stephan, played on his hockey team, was a Boy Scout and ``one of those kids that had all the potential,'' she said. ``He could have been governor or something like that.''

Joe Kalte was a hardworking teen who held down an after-school job at a pizza joint. ``God, he was a spunky dude,'' Zopp said. ``The idea that he gets run down like this, it's like he didn't get a fighting chance.''

``I guess the worst part is these kids watched the train,'' she added, her eyes welling with tears. ``I mean, the last thing in your mind is a train running you down.''

On Thursday, classes are to resume at Cary-Grove High School. The school buses will roll and the students will be back in classrooms and the gym and the cafeteria.

Said school spokeswoman Pat Deppert: ``We need to be together.''