A Conrail freight train derailed yesterday in Bowie, disrupting Amtrak passenger service between Washington and Baltimore for most of the day and temporarily displacing about 150 persons from nearby homes and businesses, officials said.

Fifteen railroad cars -- including two carrying the corrosive chemical ferric chloride -- came off the track about 9:30 a.m., Prince George's County fire officials said. No one was reported injured in the accident, which occurred near Laurel Bowie Road and Chestnut Avenue.

Postal clerk Janice Perkins was working alone at the West Bowie post office, about one block away from the derailment, just before the cars jumped off the track. "The whole building shook," said Perkins, who was one of the persons evacuated. "It felt like an earthquake."

About 15 minutes later, Perkins said, Prince George's police and firefighters were asking people to leave the area because they feared one of the tankers was leaking.

An inspection of the two tankers showed that neither was leaking, said Anthony DeStefano, a fire department spokesman. The residents, except for about a dozen whose homes and businesses were next to the accident site, were allowed to return after a couple of hours.

The derailed cars blocked all three Amtrak lines, preventing passenger trains from going south of Baltimore or north of Washington. "It's a major disruption," said Clifford Black, an Amtrak spokesman.

Express buses were used to shuttle passengers between Baltimore and Washington, Black said, and "local" buses were offered to passengers traveling to New Carrollton or Baltimore-Washington International Airport. Black said he expected normal train service to resume by this morning's rush hour. In all, he said, the derailment disrupted about 55 trains and inconvenienced about 10,000 passengers. The accident added about an hour to passenger trips, he said.

The 88-car train was headed to the Potomac Yard near Washington from Allentown, Pa., said Conrail spokeswoman Kathleen Byrne, who added that the cause of the derailment is under investigation.

A spokesman for the Du Pont Co., which manufactured the ferric chloride involved in the derailment, said the chemical is used in water treatment plants.