The Saturday night derailment of a freight train alongside Metro tracks, for the second time in three months, left thousands of Metrorail riders without service yesterday and is expected to shut down Red Line service north of the Fort Totten station until Wednesday morning.

Fourteen freight cars, including one that officials initially thought was carrying hazardous chemicals, slipped off the rails in Northeast Washington at 11:23 p.m.

They ripped up two CSX tracks and the parallel Metro tracks, spilling cars into a warehouse and a Metro high-voltage power station. No one was injured, but more than 200 nearby residents were forced from their homes for about four hours.

Although Metro was operating at the time of the derailment, no transit agency trains were near the site.

The derailment occurred just south of New Hampshire Avenue, less than two miles south of where another CSX train derailed alongside Metro tracks June 19, cutting off Metro Red Line service north of the Takoma station for three days.

Yesterday, rail service was cut off between the five Red Line stations from Rhode Island Avenue to Silver Spring but Metro provided free bus service.

Metro planned to extend rail service today from Rhode Island to Brookland and Fort Totten, and to provide bus service from Fort Totten to Takoma and Silver Spring. All service is expected to resume by Wednesday.

About 14,000 people ride the Metro Red Line north of Rhode Island Avenue on a typical Sunday.

On an average weekday morning, about 9,500 riders board the Red Line at the Silver Spring station, making it the busiest Metro station in Maryland.

About 3,500 passengers get on at Takoma each morning.

CSX officials said the cause of the derailment was unknown, but National Transportation Safety Board safety specialist William G. Meeker said a problem with one of the wheels may have caused it. "There is an indicator that one of the car's wheels left the rail just before the crash site," he said after inspecting the wreckage.

The 90-car freight train, headed from Chicago to Philadelphia by way of Baltimore, was traveling southbound at about 55 mph, which is within the speed limit, when cars numbered 45 through 58 jumped the track, said CSX spokesman Charles Castner.

The 14 cars crashed into each other, damaging more than 1,000 feet of both inbound and outbound Metro tracks and the two fences between the Metro and CSX rails.

The train's four crew members will be tested for drugs, Castner said.

CSX did not test the crew of the train that derailed in June because that incident involved no injuries and damage was less than $500,000, the criteria established by federal regulations.

CSX had no estimate of the damage caused Saturday night, but the decision to test for drugs indicates that the costs are expected to exceed $500,000, Castner said. Metro had no estimate of its damage costs.

The National Transportation Safety Board, using the same criteria, initially decided not to investigate the June 19 accident but later reversed itself and launched a special probe to look at the dangers posed to Metro cars by parallel freight tracks.

The June derailment occurred at 4:40 a.m., when Metro was not running, and no Metro trains were in the vicinity Saturday night, but the two incidents have heightened concerns about the possibility of a rush-hour nightmare.

"This is the second time that only good luck has stood between the public and a disaster," said Maryland Del. Peter Franchot (D-Montgomery County), a Takoma Park resident. "We can't count on luck to be on duty every day."

Franchot called on CSX and Metro to separate their operating schedules so the two are not on the tracks at the same time.

"Obviously it would be an economic inconvenience, but obviously two derailments back to back warrant a better response from CSX and from Metro," said Franchot. "I hate to think what would have happened if a Metro train had been there. It would have been obliterated."

CSX runs about 15 freight trains a day over that stretch of track and shares it with two Amtrak trains per day and about four commuter trains, Castner said.

Meeker, who is leading the safety board's investigation into the June crash, said the two accidents "probably are not related to one another."

But Meeker expressed similar concern about the possibility of a derailment during a busier hour.

"Our concern is that the cars on Metro could not withstand the kind of force you had in this accident," Meeker said, noting that the safety board 17 years ago warned Metro planners of such an occurrence and recommended separating transit agency and railroad tracks by height or width. "But as you can see, that has not been done. And there might be nothing we can do in the short run."

Four locomotives pulled the train, which consisted entirely of flat-bed cars carrying trailers or containers.

Eighty-eight cars carried freight, including automotive parts, mail, ink and propane, said Castner. Two cars were empty. The propane car did not derail.

One flat-bed car with two trailers carried 264 barrels that had been used to carry nitrocellulose, which is flammable and explosive under some circumstances.

The drums contained some residue of the chemical, which is used in the manufacture of plastics and some explosives, Castner said.

One trailer broke open, spilling about 25 drums.

CSX called in J&L Industries, a private company that specializes in hazardous materials removal, to clean up the drums. The D.C. Fire Department stood by with 15 pieces of equipment and 80 firefighters. The Fairfax County Fire and Rescue Department sent about 1,000 gallons of an alcohol-based foam.

Within 20 minutes of the crash, D.C. police started to evacuate residents within two blocks of the accident, near Second and Nicholson streets NE.

"I did not argue," said Vivian Tapscott, who lives on the 5700 block of Second Street NE. "I left as soon as I could and went to my mother's."

The displaced residents were taken to LaSalle Elementary School and Rabaut Junior High, where they were allowed to spend the night or go home after 3 a.m. yesterday.

Some of the evacuees grumbled when they arrived to find LaSalle locked and had to wait about 20 minutes for the shelter to be opened. But others praised the assistance effort.

"They made every effort to get us out of here as quickly as possible," said Bernard Lewis, who lives on Second Street. "And they made every effort to keep us comfortable."

One freight car smashed through the wall and ceiling of a warehouse on Second Street. The crash caused about $100,000 in damage to Regent Storage Co., a business tenant in the warehouse, said owner Wayne Woodruff.

"But thank God no one was hurt. If I'd have had a man in here, he would have been killed." he said.

Woodruff's next-door neighbor, Precise Chemical and Equipment Co., a janitorial supplies dealer, also lost part of a wall, but officials said they could not estimate the damage.

"There's nothing I can do until they move that {rail} car," Woodson said, watching the rain pour through the ceiling onto the furniture stored inside. "I just hope nothing else collapses when they lift it out."

Another car broke through the wall of a Metro high-voltage power station between the Fort Totten and Takoma stations. Metro had not determined the damage yesterday, in part because the derailment had cut Metro's power throughout that area, said spokeswoman Beverly Silverberg.

New Hampshire Avenue was closed yesterday in the area near the derailment.