FOX RIVER GROVE, Ill. (AP) _ Investigators working around the clock tried to determine today whether a malfunctioning traffic light held a school bus on railroad tracks as a train slammed into it. Residents said the light had long been a problem.

The wreck killed five students and injured about 30 others. Eleven students remained hospitalized today, four in critical condition.

Sensors embedded in the tracks are supposed to change the crossing's traffic light to green as a train approaches to allow vehicles to clear the intersection, officials said. But some witnesses reported that the light was red, which could have prevented the bus carrying 35 students and the driver from moving into the heavy morning traffic.

``There are indications that there have been previous problems at that particular crossing,'' National Transportation Safety Board member John Goglia said Wednesday night.

The town's police chief, Robert Polston, saw Wednesday morning's crash because he was checking out recent reports of problems with the light. Village officials have said he would not comment because he was an eyewitness.

Residents said the crash site was known locally as a hazard because of what they said was poor coordination between the gates and signals protecting the railroad crossing and the traffic light at an intersection just beyond it.

``People have been saying something's going to happen because it's just not timed right,'' said Jim Homola, who was in his car behind the bus when the train hit.

``It was an accident waiting to happen,'' said Pat Ward, who works at a convenience store half a block from the crash scene.

She said the gates at the crash site closed on her husband's semi-trailer truck while he waited at the intersection just hours before Wednesday's fatal crash. She said he edged his rig into traffic to get off the tracks.

Investigators overnight began testing the light and were seeking police phone logs to check for complaints. Before dawn, technicians in white helmets were testing signals at the crossing. Early morning commuter trains crawled through with horns blowing, and a woman scurried by to lay a bouquet of lilies at the scene.

Regardless of whether the light was red or green, some witnesses said there was no car ahead of the bus and the driver could have moved forward. A crossing gate had come down behind the bus.

The bus was en route to the 1,400-student Cary-Grove High School in Cary, near this bedroom community about 40 miles northwest of Chicago.

The Chicago-bound express train was traveling between 50 and 60 mph and sheared the body of the bus off the chassis, spinning it around 180 degrees. Nobody on the train was injured.

Federal officials said the bus is designed to break apart like that in a high-speed crash to put distance between the occupants and the gas tank.

When 15-year-old Zach Davis saw the 620-ton train bearing down on him, he had one thought: ``I'm going to die.''

From his seat in the front of the bus, the teen remembers the bus stopped once before the railroad tracks, just like it's supposed to, then went forward and quickly stopped again for a red light.

After the accident, he said, it was ``hectic, very hectic. Moms screaming, trying to find their kids.'' Zach escaped with only whiplash injury.

The bus driver, Patricia E. Catencamp, was taken to a hospital for evaluation. Crash investigators declined to discuss the driver.

The secretary of state's office said the 54-year-old woman had been licensed to drive a school bus since 1987 and had a flawless record. But school Superintendent Joseph Saban said she was not the regular driver on that particular route; she was filling in for the day.

The crossing was guarded by a gate, bells, flashing lights and signs, but there was little space between the stoplight and the tracks, said Chris Knapton, a spokesman for Metra, the agency that operates Chicago's suburban commuter trains.

Mark Davis, a spokesman for Union-Pacific, which employs the train crew, said the engineer tried desperately to stop the train. ``He slowed down. Then he applied the emergency brake, then he got on the horn.''

Investigators about 12 hours after the accident removed the remains of the bus from the scene, where residents in this close-knit community known as ``the Grove'' started an impromptu shrine with bouquets of flowers and flickering candles.

``I think they're here because of the disbelief. They don't believe it,'' said Sue Ramirez, who lives just about a block from the scene. ``It's something you watch on CNN or the national news, but not here, it doesn't affect your own.''

The dead were identified as: Michael B. Hoffman, 14, Shawn P. Robinson, 14, Joseph A. Kalte, 16, Tiffany Schneider, 15, and Jeffrey J. Clark, 16.

Jason Kedrok, 16, was wearing a hospital bracelet and had bruises on his face and arm when he showed up at the accident scene in the afternoon to look at the wreck he had survived.

``Just looking at it now,'' he said, ``I can't believe I got out of it.''