Kirby Corporation is a domestic tank barge operator, transporting bulk liquid products throughout the Mississippi River System, on the Gulf Intracoastal Waterway, coastwise along all three United States coasts and in Alaska and Hawaii. The Company, through its subsidiaries, operates in two segments: Marine Transportation and Diesel Engine Services. The Company, through its Marine Transportation segment, is a provider of marine transportation services, operating tank barges and towing vessels transporting bulk liquid products throughout the Mississippi River System, on the Gulf Intracoastal Waterway, coastwise along all three United States coasts and in Alaska and Hawaii. Its engine services segment, sells replacement parts, provides service mechanics to overhaul and repair medium-speed and high-speed diesel engines, transmissions, reduction gears, pumps and compression products, maintains facilities to rebuild component parts or entire medium-speed and high-speed diesel engines.