Hazards posed by Metro's oldest rail cars, the 1000 series, have been a continuing safety concern. In July, the Tri-State Oversight Committee (TOC), which monitors Metro's safety, summarized exchanges between Metro, also known as the Washington Metropolitan Area Transit Authority (WMATA), and the National Transportation Safety Board (NTSB). "6/22" refers to the June 22 Red Line crash. "#6" is an NTSB recommendation to replace or reinforce the cars. "Bellying" refers to moving cars to the center of a train.