Kirby Corporation is the domestic tank barge operator, transporting bulk liquid products. The Company, through its subsidiaries, operates in two segments: Marine Transportation and Diesel Engine Services. The Marine Transportation segment is a provider of marine transportation services, operating tank barges and towing vessels transporting bulk liquid products. The Diesel 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, transmissions and entire reduction gears, and manufactures and remanufactures oilfield service equipment, including pressure pumping units. Its customers include oil service companies, offshore fishing companies, nuclear power industry, compression companies and construction companies, among others.