Clessie Cummins

Clessie Lyle Cummins was an inventive mechanic and entrepreneur whose vision reshaped American transportation. Raised in Columbus, Indiana, Cummins learned engines from an early age. With support from investor W.G. Irwin, Clessie founded the Cummins Engine Company in 1919, starting in a small shed beside the Cerealine factory.

His early F-model marine engine proved the company’s first success, laying the foundation for later designs. The versatile U-model expanded into marine and highway use, where Cummins personally tested engines on marathon drives. But it was the revolutionary H-model—introduced in 1932 as the first high-speed, lightweight highway diesel—that brought diesel power to America’s trucks and remained in production into the 1960s.

Cummins was a master promoter, proving his engines’ durability in dramatic public demonstrations. In 1931, a Cummins-powered Duesenberg raced at the Indianapolis 500, showcasing diesel’s endurance. The following year, a diesel-powered Mack bus made headlines by driving from New York to Los Angeles in just 97 hours—faster than any express train of the day.

Supported by talented colleagues like Hans Knudsen, who refined the epochal H-series design, Cummins transformed skepticism into acceptance. His relentless testing, ingenuity, and showmanship established Cummins as a global name in diesel innovation.

Though he began with little more than mechanical skill and determination, Clessie Cummins built an engine company that helped fuel the modern age of trucking, buses, and industry.