Investigations into Monday’s Washington Metrorail crash honed in on why the train’s computer system didn’t slow it down even though there was evidence the conductor tried to engage the emergency brake, The New York Times reports. All Metro trains were running in manual mode Tuesday as a precaution against crashing, but at the time of the accident the train was operating in automatic mode. "'That train was never supposed to get closer than 1,200 feet, period,'” said Jackie Jeter, president of a union that represents Metro workers. Nine people died and 76 were injured—six critically—when a commuter train on D.C.'s red line, the Metro's busiest line, rammed into the back of a stopped train during rush hour. The dead include the operator of the trailing train, Jeanice McMillian. In 2006, the National Transportation Safety Board had warned Washington Metrorail officials that its aging trains needed to be phased out of its transit system. The cars involved in the crash were some of the oldest in the Metrorail.