The Cummins Engine Company was founded in Columbus, Indiana, in 1919 by William Glanton Irwin and Clessie Cummins, a local mechanic. It focused on developing the diesel engine invented 20 years earlier, but in spite of several well publicized endurance trials, it was not until 1933 that their Model H, used in small railroad switchers, proved successful. Cummins N Series engines became the industry leader in the post-World War II road building boom in the United States, with more than half the heavy duty truck market from 1952 to 1959. In the 1960s, the company opened an assembly plant in Shotts, Scotland (closed in 1996). By 2013, Cummins had operations in 197 countries and territories.
Cummins Engine Business Unit consists of Aftermarket support, Mid-Range, Heavy-Duty, and High-Power Engines. Cummins manufactures and markets a complete line of diesel and natural gas-powered engines for on-highway and off-highway use. Its markets include heavy-and medium-duty truck, bus, recreational vehicle (RV), light-duty automotive and a number of industrial uses including, construction, mining, marine, oil and gas, railroad and military equipment. For the general public, the most visible Cummins product may be the 5.9-liter in-line six-cylinder engine used in the Dodge Ram light duty pickups starting in 1988.5. In 2007.5, a 6.7-liter version of the Cummins straight six engine became optional on the RAM pickup. In 2008, Cummins was a named defendant in a class action suit related to 1998-2001 model year Chrysler Dodge Ram trucks, model 2500 or 3500, originally equipped with a Cummins ISB 5.9 liter diesel engine built using a pattern 53 Block. The case has been settled, but some qualified Chrysler owners may receive $500 for repairs to the block, which was alleged to crack and create a coolant leak. Cummins has a technical centre in Darlington, England, where it develops products for the European, Middle Eastern, and Asian markets.