Where Kirby hauls cargo, the only curbs are riverbanks -- the company is the largest inland tank barge operator in the US. Its fleet, operated by subsidiary Kirby Inland Marine, consists of over 890 barges and about 240 inland towboats with a transportation capacity of 17.9 million barrels. The vessels are used to transport liquid bulk cargo: petrochemicals, crude and refined petroleum products, and agricultural chemicals. Its Marine Transportation segment (inland/offshore operations) is joined by its Diesel Engine Services segment, which is a leading provider of diesel engine services and parts for marine, rail, and power generation customers.