One of the most famous inventions in San Joaquin County history is the track-laying tractor, which today we associate with the name Caterpillar. This milestone in technology was well-suited to the deep peat soil of the Sacramento-San Joaquin Delta and will be linked forever to the name of Stockton inventor and entrepreneur Benjamin Holt (1849-1920).
The Holt 75 Caterpillar tractor at left was purchased new in 1919 by Barrett Brothers Farms of Antelope, Sacramento County, and used well into the 1930s. In 2010, the estate of Gerald Barrett donated it to the Museum. Currently, volunteers and Museum staff are restoring the tractor with the goal of making it fully operational.
Built between 1906 and 1925, the Holt 75 was the best selling of Holt tractors. It had a reputation as a quality farming tractor and was used in World War I to haul artillery and munitions.
Gasoline-powered tractors such as these were a big improvement over steam-powered traction engines. Steam boilers exploded if steam pressure got too high or if water levels in the boiler got too low. Cinders from the steam engines often started fires, especially in the dry fields of grain common in San Joaquin County. And because they had to carry hundreds of gallons of water, steam traction engines were very heavy—often fifty thousand pounds—which, of course, caused them to sink into the deep peat soils of the Delta.
The Holt 75 Caterpillar Tractor had a seventy-five horsepower gasoline engine, was twenty feet long, weighed twenty-four thousand pounds (the weight of six and one-half Honda Accords), and distributed its weight more evenly than predecessors because of its track-laying propulsion system. In eleven years of production, about 4,160 Holt 75s were made, 1,810 of which were ordered by the military (75 percent by the British).