PALATKA, Fla. (AP) _ An Amtrak passenger train derailed today and hit two unoccupied houses, leaving cars snaking across a city street and sending at least 31 people to hospitals, police said.

No deaths were reported on the Silver Meteor, carrying about 175 people from New York City to Tampa, authorities said. Four people with serious injuries were flown by helicopter to out-of-town hospitals.

Three-year-old Billy Donald of Clearwater was asleep on his mother Teri's lap and was thrown into the back of the seat ahead of them when the cars left the track.

''The train fell down,'' said the boy, who was clutching a teddy bear given to him by rescue workers at a community center where passengers were taken for emergency medical evaluations.

''I thought we were having an earthquake. Really truthfully it just shook the whole building,'' said Gerri King, who works nearby. ''I knew a train had derailed or something because you cannot see the house when the train passes, and you could see the train behind the house.''

A woman and a boy, whose names were not released, were in fair condition early this afternoon at University Medical Center in Jacksonville, and two patients were taken to Shands Medical Center in Gainesville, spokesmen said.

A total of 27 people were taken by ambulance or school bus to Putnam Community Hospital for treatment of minor injuries, police said.

''We're seeing sprains, cuts, real minor stuff,'' said spokeswoman Abby Stivender.

The office of U.S. Rep. Craig James, a Republican from DeLand, confirmed his wife, Kitty, was on the train, but the staff in his district office had no information on whether she was injured.

The train, with one engine and eight cars, derailed at 11:25 a.m. about three blocks from the depot in Palatka, which is in northeast Florida south of Jacksonville.

The train left New York on Monday and was scheduled to arrive at Tampa at 3:02 p.m. today, said Anne Marrinan, an Amtrak spokeswoman.