Image courtesy of https://auto.howstuffworks.com/horsepower.htm
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The photo below was taken in 1918-- when the first Calaveras Dam was being constructed. These workers are excavating in the dam's foundation. They're using using 4-mule carriages(4-horsepower) to do the job. Each power train (4-mule carriages) transport approximately 4 cubic yards per load at a speed of 1 to 2 mph.
Fast forward a hundred years. The photo below was taken at the new Calaveras Dam as workers were excavating the new core. The workers in this photo are doing the same job with a Caterpillar Motor Scraper with a 450 horse power engine capable of carrying 30 cubic yards at a speed of 25 to 30 mph.
Although times have changed, sometimes the methods don't.
See you around the valley!