MBTA testing trolley collision system

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.