These were put into service in the late 1890s and originally many CD 269 Jumbos (most likely Oakmans) were installed filling each horizontal cross-beam as you see here (upper left corner). This was at the eastern end of the Boston Elevated Railway (later known as the "Orange Line"); the heavy DC circuits originating at a power source a mile or two away. The overhead DC cables along the stretch where the Jumbos were gradually removed and re-routed. Just about all of the insulators were removed too. In a few spots one could see a "crossarm" or two with old Jumbo pins, very worn from many years of exposure to the weather, pollution, etc. This method of construction changed at Dudley station (the "Orange Line") and was an east-west route. From that point for the next 5 or 6 miles, CD 267s, 267.5s and heavy white porcelain cleats were employed. Typically there were four cables on heavy duty beams in between the inbound and outbound tracks. The "Orange Line" or "El" was dismantled in 1988.