A key circuit on the train track near Monday's derailment in Washington, D.C., was apparently not operating as it should have been, raising the possibility that the Metro train that crashed into another one may not have known to slow down, accident investigators said today.
Investigators tested six circuits between the two stations where the crash occurred. Five of those performed as expected, according to National Transportation Safety Board investigator Deborah Hersman. Such circuits let trains know how fast to go and provide them with information about whether there's another train up ahead.
But one circuit showed what Hersman described as an "anomaly" and monitored a 740-foot section of the track. Investigators are putting a stand-in train on the track tonight to conduct additional tests.
The NTSB also said it has now looked at train records and found no indications of overdue maintenance despite earlier reports that the brakes on the train may have been behind schedule for a check-up. The train was last examined in late May.
Nine people died and another 76 were taken to area hospitals when one Metro train struck a stopped train in front of it near the Fort Totten station on the city's red line. The train that was struck was pushed forward about seven feet, Hersman said today.
"We do have an independent train system ... [but] let's not try and disperse the blame. Let's put it on the decision makers and the leaders," Fenty said on "Good Morning America".
Fenty said that while replacing or retrofitting the cars "to make them more crash resistant" would have been expensive, "lives are more important than finances."
Fenty's comments came as the NTSB learned that the operator of the D.C. Metro train that crashed into a stopped train ahead of it likely hit the emergency brake before the impact. Hersman said this afternoon it appears the operator applied the braked 300 to 400 feet prior to the crash site. NTSB investigators at the scene today found "bluing" on the track, indicating braking prior to the collision. They do not yet know how fast the train was going when it collided with the other, but said they will, at some point, be able to ascertain that information.
The train operator, 42-year-old Jeanice McMillan, who had been on the job for four months, was among those killed in Monday's crash.
Investigators were able to determine that the train was running on automatic mode at the time of the crash and are investigating why built-in safety features of that system did not prevent the crash. The track circuits are a critical part of the automatic train control system.
Officials said Metro trains travel above sensors along the rail that can automatically detect when trains are getting too close to one another. The computerized system is designed to stop them from coming within 1,200 feet of each other.
"What causes us concern the most is the fact that this was not supposed to happen," Jackie Jeter, president of Amalgamated Transit Union Local 689 said Tuesday. "There are safety mechanisms that are on place on the trains to prevent this type of accident. And, for me, as president of the union and as a train operator, I have to wonder why didn't those safety mechanisms kick in and prevent it."
Train recorders will provide insight into what happened as the information is evaluated over the next few days, former National Transportation Safety Board investigator Barry Sweedler said. The train that was hit had several recorders on it, but the one that collided into it didn't have any.
Faces of the Dead: Family Members, Servicemen
The victims of Monday's train crash ran the gamut from a young mother of two and a military officer to a man on the way to his night shift and a 59-year-old woman who was making plans for the trip of a lifetime.
The military officer killed in the crash was Major General David F. Wherley Jr., who died alongside his wife, Ann. Both were 62. Wherley, a career military man had recently retired as the head of the D.C. National Guard. It was his order that scrambled jets over Washington, D.C., Sept. 11, 2001.
"He was as fine a public servant, as dedicated to the United States of America as anyone I have ever met," Fenty said.
Also on the train was 40-year-old Ana Fernandez, killed while on her way to a nighttime cleaning job. She left behind six children.
Passenger Dennis Hawkins, a 64-year-old retired teacher, died while on his way to teach a Bible class.
And Lavonda King, just 23 years old, was killed as she took the train to pick up her two sons from daycare. Her mother said King had dreamed of a better life for her boys and had recently signed the paperwork to open up a beauty salon.
McMillan, one of the earliest faces of the train accident, was also a mother. She was killed while operating the train that rear-ended the other train.
The son she raised by herself had started college in the fall. Her family said she took pride in her work on the train and ironed her uniform nightly.
"She loved the train. She would talk about what she did at work, or how this works," said her brother, Vernand McMillan.
McMillan recently graduated from bus driver to train operator. Her favorite part of the job? Her relationships with the passengers.
NTSB Had Warned Metro Trains Could Be Dangerous
No matter what caused the accident, passengers traveling in the approaching train were in an older car that did not protect them as well as it should have.
Despite the two NTSB warnings, transit officials had refused an upgrade because it would be expensive and complicated.
In 1996, a Metro train of the same series failed to stop and crashed into an unoccupied train in what the NTSB called "catastrophic failure." After the crash the NTSB recommended a comprehensive evaluation of the cars. In 2002, D.C. Metro declined to make any changes. A similar crash took place in 2004, and the NTSB reiterated its warnings.
"In 2006 [the NTSB] asked them to look at old cars," Hersman told "GMA." "They did not retrofit the cars to the standard the safety board was looking for."
Hersman emphasized that the NTSB's role was to make recommendations, and that it was up to local and federal authorities to decide whether to act based on those recommendations.
"The Safety Board is in the business of investigating accidents and making recommendations," Hersman said. "The safety board is going to be looking very closely to what has been done."
ABC News' Lisa Stark, Matt Hosford and Kate Barrett contributed to this report.