UPPER SANDUSKY, Ohio (AP) _ An Amtrak passenger train broadsided a CSX train Sunday, injuring four people, knocking a shack into a swimming pool and throwing a freight car into a homeowner's yard, authorities said.

The 116-car freight train was carrying ''everything from sand to syrup,'' including carbolic acid in one car, but none of the cargo spilled, said Andrea Just, a CSX Transportation spokeswoman in Baltimore.

The accident occurred at 5:43 a.m. when the Amtrak's Broadway Limited train traveling from New York City to Chicago hit the freight train bound for Newport News, Va., from Chicago, at a crossing, said Deborah Hare, an Amtrak spokeswoman.

The cause of the accident near this north-central Ohio city was under investigation by the National Transportation Safety Board. Ms. Hare said crew members of the Amtrak train have undergone required drug and alcohol tests and the samples have been sent to a laboratory for analysis.

''My understanding is the Amtrak was moving very slowly,'' Ms. Just said. The CSX train was traveling at about 35 mph, she said.

The collision threw a freight train into two outbuildings, knocking one into a pool, Ms. Just said.

The owner of the house, Mike Swinehart, said he found the car in his yard when he arrived home. Bob Mackling, who was asleep in the house at the time, was unharmed and said he was not awakened.

Two Amtrak engines and a baggage car also jumped the tracks, Ms. Hare said.

The injured were taken to Wyandot Memorial Hospital, where two Amtrak crew members remained hospitalized Sunday.

Train fireman Dennis Schleppi, 41, of Fort Wayne, Ind., underwent surgery for internal injuries and was in fair condition, said supervisor Thelma Warfel. Conductor Forace Brewer, 63, of Bluffton, Ind., was admitted to the coronary care unit in fair condition with a possible heart attack, she said.

An Amtrak engineer was treated for a broken foot and a 76-year-old passenger was treated for chest pains. Both were released.

Sheriff Michael R. Hetzel said about 230 people were aboard the Amtrak train. Buses were brought from Toledo to take them on their way.

An official of the Wyandot County Sheriff's department who declined to give his name said the crossing had been cleared by Sunday night and that both trains had resumed their trips.