How a Prototype Caterpillar Engine Changed an Industry 

Before Benjamin Holt and C.L. Best merged their companies to form Caterpillar Inc. in 1925, both men studied the feasibility of installing diesel engines in their earthmoving machines. Although the first American diesel engine appeared in 1898 and was more efficient than a gasoline engine, it was large, heavy, and limited to large stationary and marine applications.

Then came the idea of putting a diesel engine in a tractor after Best attended the World's Fair in San Francisco in 1915. Years later, Caterpillar's prototype D9900 diesel engine was born. Nicknamed 'Old Betsy,' it might be the company's most valuable historical artifact. It represents the company's earliest energy transition – going from gasoline power to diesel power. 

In this latest Diggin' Into History episode, Corporate Heritage Archives Manager Lee Fosburgh and host Rusty Dunn show how this one-of-a-kind engine changed the company and an entire industry almost overnight – and how it was almost lost to history forever.