Six persons are known to have been killed and twenty-five others are pinned in the wreckage of a two-car elevated train bound from Bay Ridge to Manhattan, which jumped the track and dropped to the street at Fourth and Atlantic Avenues, Brooklyn, N.Y. this afternoon. The cars fell upon two automobiles which were passing in the street below. They are still under the wreckage. Firemen are at work extricating the dead and injured. The location of the accident is one of the busiest intersections of Brooklyn.