BOSTON (AP) - The Massachusetts Bay Transportation Authority is
preparing to test trolley collision-avoidance technology in the
aftermath of two Green Line crashes.

The system uses radio waves and increasingly rapid beeping to
alert drivers as they approach another train. If the driver fails
to stop, it automatically stops the train.

The system will be deployed first on the Mattapan Line, a
two-mile stretch of trolley tracks, with the aim of evaluating its
applicability on the larger Green Line.

A collision in May 2008 killed a trolley driver, while a second
one this May injured nearly 50 and caused an estimated $9 million
in damage.

At the time, MBTA drivers complained the Green Line lacked more
elaborate computerized collision-avoidance systems used on the Red
and Orange lines.