By Glen Johnson, Associated Press
The National Transportation Safety Board plans Tuesday to issue its final report on an MBTA Green Line trolley crash in Newton that killed the operator and injured five others.
The board has scheduled a public hearing Tuesday in Washington to discuss its findings in the crash on May 28, 2008, when a train operated by Terrese Edmonds slammed into a trolley just outside the Woodlands station.
Nearly a year later, a second Green Line trolley collision in Boston on May 8 was blamed on a text-messaging driver. Operator Aiden Quinn, 24, was indicted Wednesday on charges of grossly negligent operation in the crash that injured more than 50 people.
Both crashes prompted talk of an automatic braking system, but that talk has been muted since nine people died last month in the crash of a Washington Metro train that had been running on automatic.
Tuesday's hearing is aimed at answering a vexing question about the May 2008 accident: What happened?
Immediately after the crash, officials refuted reports Edmonds may have been distracted by her cell phone or text messaging.
Meanwhile, NTSB investigators ruled out track and brake problems, as well as any drug or alcohol influence on the 24-year-old Edmonds. They determined her train was moving at an excessive rate -- about 38 miles per hour -- when it struck the rear of another westbound train moving only 3 to 4 miles per hour. Edmonds should have been traveling no more than 10 miles per hour after a mandatory stop at a nearby station, they said.
Investigators conducted a so-called "sight distance" reconstruction about the same time as the accident to glean what Edmonds saw before the accident, and whether her view was obstructed. Since then, the NTSB has conducted its work largely out of public view.
Both the 2008 and 2009 crashes triggered calls for a computerized automatic braking system on the Green Line, similar to those already used on the Red and Orange lines.
Massachusetts Bay Transportation Authority General Manager Daniel Grabauskas initially deflected such requests from the train operators' labor union. He said automated systems would create gridlock on the narrow, winding routes of the Green Line. By contrast, the Red and Orange lines have long runs of straight tracks.
Grabauskas also said drivers had three ways to stop trains, and the latter crash was caused by distracted driving.
Yet last week, the T announced it was conducting a test on its Mattapan trolley line to determine if an alternate automated braking system -- similar to radiowave systems that sound back up warnings in automobiles -- could be installed on the Green Line.
Meanwhile, Washington's commuter agency has gone the opposite way.
It's been running its system on manual control since one of its trains careened into the back of a stopped train on June 22.
The union representing Metro drivers also asked that operators be allowed to choose whether to use automatic mode, which is typically employed during rush hour.
The NTSB is investigating that crash, as well as this May's MBTA crash.