IN the shadow of Boston's historic Trinity Church, just feet below the finish line of the famed Boston Marathon, two subway cars collided July 17, jolting passengers and sparking safety questions on a mode of transportation considered to be virtually accident-free.
''Basically, on a subway system, cars shouldn't hit each other,'' says Joseph Rappaport, spokesman for the Straphangers Campaign, a New York advocacy group for commuters. ''It should never happen.''
But it happened just last month in New York City, when automated brakes failed to keep two trains from crashing, killing one and injuring 54. Four months before that, seven were injured as two commuter trains slammed into each other. And on the same day as the Boston accident, a subway train derailed in Baltimore, injuring two dozen.
Nationwide in 1994, 93 people were killed on rapid transit systems, compared with some 22,000 in passenger cars and 20 traveling by bus.
''Obviously if there's a trend, we need to address any safety issues that may be involved,'' says Pat Cariseo, spokesman for the National Transportation Safety Board.
The July 17 crash injured 32 when an underground trolley car operator rammed into the train in front of her. The collision took place on the oldest subway line in the country, which dates back to 1897.
Though no cause has yet been named in this crash, experts say subway wrecks are usually caused by a combination of driver and equipment failures. In most systems today, if a driver disregards a signal, an automatic brake kicks in. When this automation fails, accidents often occur. The Boston subway line did not have automated brakes. Experts say operator training and equipment upkeep are the most important ways to keep subways safe.