THE PROBE: Experts Suspect Failure Of Signal System, Operator Error
Metro Had Planned to Phase Out Older Cars, But They Remained in Fleet

By Lyndsey Layton
Washington Post Staff Writer
Tuesday, June 23, 2009 1:21 PM

Federal investigators will focus on communication between operators, a possible failure of the signal or automatic operations systems and potential operator error as they probe yesterday's Metrorail crash that killed nine and injured scores more, an official with the National Transportation Safety Board said this morning.

Board member Deborah Hersman also said the southbound train that crashed into another train on the Red Line near Fort Totten was one of the oldest in Metro's fleet. Five years ago, federal regulators said that model car should be strengthened to better protect occupants in the case of a collision.

"We recommended to either retrofit those cars or to phase them out of the fleet," Hersman said. "They have not been able to do that and our recommendation was not addressed. So, it has been an unacceptable status."

Metro officials have said that it was not clear that attempts to make the aging rail cars more crash-resistant would be successful. Retrofitting would not only be expensive, but could create new problems with propulsion and other aspects of operation, transit officials said at the time. In addition, such retrofitting was deemed too expensive for the cash-strapped system, especially because the cars are due to be replaced as soon as possible, officials have said.

Metro decided it would phase out the old cars as it purchased new vehicles. But today, all the old cars remain in service and comprise about one-third of the Metro fleet.

The 33-year-old Metrorail system was designed with a fail-safe computerized signal program that is supposed to prevent trains from colliding. The agency's trains are run by onboard computers that control speed and braking. Another electronic system detects the position of trains to maintain a safe distance between them. If they get too close, the computers automatically apply the brakes, stopping the trains.

These systems were supposed to make yesterday's crash impossible.

But four years ago, in an episode eerily similar to yesterday's, the signal system briefly failed in the tunnel between Foggy Bottom and Rosslyn, forcing two quick-thinking operators to stop their trains manually to avoid a crash.

In the June 2005 incident, the operator of one train noticed that he was getting too close to the train ahead. The signal system was telling him the track was clear, but he hit the brakes. The operator of a third train on the line hit the emergency brakes on time, too.

Metro officials were stunned by the events, which they said at the time had not happened before, and launched an investigation. It was unclear last night whether they ever found a cause.

In yesterday's crash, it appeared that the operator of the train that crashed did not apply the emergency brakes, also known as the "mushroom." Experts said the train appeared to be traveling fast before impact because the force pushed the first car of the train on top of the train ahead. Witnesses on that train also reported that the train did not brake before impact.

There was no reason to think that the operator, whom Metro officials have identified as Jeanice McMillan, did not spot the train ahead of her yesterday. The weather was clear, and the trains were not in a tunnel.

"It doesn't look like she hit the brakes," said a train safety expert, who asked not to be identified because the crash is under investigation. "That's why you have an operator in the cab. She should have been able to take action. That's what they're there for."

Other possible factors in the crash include a medical emergency that incapacitated MacMillan or a catastrophic failure of the braking system.

The trains in yesterday's crash were supposed to be in automatic operation, which means the operators would have been relying on the computerized system to run the trains. The only function required of a train operator during automatic operation is to close the doors after a station stop. Some safety experts said operators can "zone out" during computerized operation because they don't have to pay as close attention as when they manually run trains.

During the past decade, Metro has struggled with troublesome communications relays. The agency tore out all 20,000 trackside relays in 1999 after discovering that a small portion designed to last 70 years were failing after 25. They sent erroneous instructions to trains on several occasions. One train was told to travel 45 mph on a stretch of track with a 15 mph speed limit; another was directed to travel at zero mph when it should have been ordered to move at 15 mph.

The manufacturer, Alstom Signaling, replaced the relays in 2000, under a contract with a 40-year warranty. Alstom also manufactures the signal system that Metro uses.

The rail cars that made up the train that crashed into the rear of the other train and vaulted over it were made by Rohr Inc. They are the oldest in Metro's fleet, about 33 years old. The Rohr cars were rehabbed recently -- stripped down to their metal frames and rebuilt with new parts -- to try to extend their lives.

After the a Red Line train rolled backward on the tracks near Woodley Park in 2004, plowing into another train and injuring 20, Metro officials discovered the Rohr cars lacked a safety measure known as rollback protection that the rest of the fleet had.

Officials weighed whether to retire the cars. But ultimately, the agency opted to keep them in service because it said it could not afford to replace them. The Metrorail system has about 300 Rohr cars.

Rollback protection does not appear to have been an issue in this crash.

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