(The following story by Matthew L. Wald appeared on the New York Times website on September 13.)
WASHINGTON, D.C. — Whatever Metrolink’s initial assertion about the cause of the deadly train crash Friday in Los Angeles, there is still room for a thorough and revealing investigation, safety experts said.
If an engineer did run a red signal, as a Metrolink spokeswoman said Saturday, the first question would be why.
“They are basically putting the whole burden of this accident on the shoulder of the operator,” said Najmedin Meshkati, a professor of industrial and systems engineering at the University of Southern California. “This is really like blaming the victim. We need to know, Why did he fail to respond to this signal?”
Did backup systems fail, or were they not used when they should have been, Dr. Meshkati asked.
The National Transportation Safety Board, which despite Metrolink’s admission will coordinate an investigation into the crash, has a history of turning up not-so-obvious causes in train wrecks and other accidents.
When two commuter trains collided in Hoboken, N.J., in February 1996, the early supposition was that an engineer, working a 12-hour shift, had fallen asleep. He died in the collision, but the safety board found that he had become colorblind because of diabetes and could not read the signal, and that his employer, New Jersey Transit, had failed to detect the problem. The board, known for its thoroughness, had found the clue in the engineer’s medicine cabinet.
The safety board sent a team of 14 experts to California, and the Federal Railroad Administration sent nine. Officials from Metrolink and Union Pacific, the operator of the freight train struck by the commuter train, as well as unionized railroad workers and workers from the State of California, will also take part in the inquiry.
Once the wreckage is cleared away, a standard step will be to see whether the signal system was working properly. Then visibility tests will be conducted using identical equipment, at the same time of day, so the angle of the sun is the same.
Remains of the crew members are typically subjected to forensic toxicology tests to detect signs of impairment from drugs.
Investigators have not yet retrieved the “event data recorder” from the locomotive of each train. It records the speed, direction, throttle position and brake application. The authorities will be looking to see whether the brakes were applied on either train and, if so, whether they were effective.
The crash is certain to revive a debate over “positive train control,” which takes over if an operator fails to slow or stop when a signal says to do so.
There are several forms of positive train control. One uses radio signals broadcast from the side of the tracks and received by the locomotive. In another, the train uses G.P.S. to figure out its own position, much as a car does, and compares it with information received from the rail system about where it is authorized to operate.
An analysis of 195 train collisions in 2006 found that 90 percent were caused by “human factors,” like inattention, medical incapacitation and distraction.
For years, the safety board has recommended that such systems be made mandatory, and some railroads have adopted them.
A spokesman for the Federal Railroad Administration, Steve Kulm, said, “There are still technical challenges and financial issues that need to be overcome” before positive train control can be mandated.
His agency rewrote the regulation covering signals and train controls in 2005, for the first time in 20 years, he said, “to take advantage of all the technological development that has happened since the early 1980s and to encourage the development and deployment of positive train control.”
“There are railroad executives and Federal Railroad Administration people who are in effect willing to accept a number of these types of crashes each year,” said Barry Sweedler, a safety consultant who retired from the board in 2000 after 30 years. Such systems should be installed first, he said, on tracks that carry passenger trains, because the potential for casualties there is much higher.