HYDER, Ariz. (AP) _ An Amtrak train derailed today in the rugged Arizona desert after someone sabotaged the tracks, killing one person and injuring more than 100 as rail cars hurtled off a 30-foot-high bridge.

Three cars landed in a dry streambed 50 to 60 miles southwest of Phoenix.

The train, the Sunset Limited, was bound for Los Angeles from Miami and was carrying 248 passengers and 20 crew members when it derailed around 1 a.m.

Two sleeper cars and a diner plunged off the bridge. In all, both locomotives and the first eight of the train's 12 cars derailed, Amtrak said.

Joyce Matthews, 49, of British Columbia, was on her way to Disneyland with her 24-year-old daughter. She was asleep when the train derailed.

``There was a loud roar and everything was shaking. It was beginning to tilt and then everything just shook and stopped,'' Matthews said.

``We don't believe it's an accident,'' said Maricopa County Sheriff Joe Arpaio, whose department is the lead agency handling the accident. ``We found some information or evidence at the scene. I'm not about to talk about it right now.'' He said tracks had been tampered with, but gave no detail.

He said two people found at some distance from the scene were questioned, but authorities don't believe they have anything to do with the accident.

An engineer had reported seeing something unusual, sheriff's Sgt. Tim Campbell said without elaborating. The FBI was investigating, said Jon Poston, spokesman for the state Corporation Commission, which regulates railroads.

One person was killed, 12 were seriously hurt and about 100 others suffered less serious injuries, Campbell said. Amtrak said the dead person was believed to be a crew member.

The scene could be reached by road by four-wheel-drive vehicles only with difficulty. The rescue was carried out almost entirely by air.

It appeared the locomotives had made it across the bridge when the derailment occurred.

The train sat with the engines upright, one car behind them tilting toward the streambed and the next three cars lying in the bed, with little visible damage. The remaining cars sat upright on the far side of the streambed.

Brian Hamblet of Los Angeles compared the experience to the earthquake that struck his city in January 1994 _ ``only we were falling 25 feet through the air. The whole thing happened like in slow motion. It was like taking a roller coaster ride.''

A triage center was set up on sandy desert soil next to a dirt road about six miles from the accident scene. Medical personnel in lab coats bustled alongside military units in camouflage as helicopters landed nearby with injured passengers. A fire truck sprayed the landing pad with water in in an attempt to control dust whipped up by the choppers.

``We've got helicopters from all over the state, including the military. They're bringing all the patients out to the landing zone, where they're being transferred to various ambulances,'' Campbell said.

The three cars that fell into the streambed were near the front of the train.

In Phoenix, hospitals reported admitting at least 24 including one woman who was listed in critical condition. One of those hospitalized was a 31-year-old woman who was on her honeymoon. She was listed in good condition. Other passengers were treated at hospitals and released or treated at the scene.

The accident site is 27 miles east of this small town in Yuma County and about 20 miles north of Interstate 8, which runs through southwest Arizona.

The train left Miami on Friday, but because of Hurricane Opal, the section of the journey from Jacksonville, Fla., to New Orleans was made by bus rather than by train, said railroad spokesman Stephen Taubenkibel. The regular route, about 3,000 miles, passes through Florida, Alabama, Mississippi, Louisiana, Texas, New Mexico and Arizona on way to California.

Two years ago, Sept. 22, 1993, an eastbound Sunset Limited train derailed into a bayou near Saraland, Ala., killing 47 people. It was the worst accident in Amtrak's quarter-century history. An investigation found that a barge lost in fog had struck the bridge shortly before the derailment, knocking the rails out of alignment.

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EDITOR'S NOTE _ Amtrak officials say people who want to find out if their relatives were aboard the Los Angeles-bound train that derailed in Arizona can call 800-523-9101. The local chapter of the American Red Cross is offering information, only to passengers' relatives, at 602-336-6681.