My grandfather, a U.S. Marine, witnessed this and I would like to know more about it.
Same way factories were removed from Germany after WW1, WW2 and how the Soviets moved factories in 1941 and 42.
They would methodically take the factory apart, labeling everything, crate it up, put it on a train, boat or ship. Transport it to the new site, then reassemble it.
Apparently, when the Soviets were building factories in the 1930s, they had an idea that someday factories might have to be relocated, but there weren't firm plans for it.
The USSR did this in eastern Europe and Germany as well, it was because the USSR itself suffered heavily during the war with its economy devastated. Looting machine tools and other forms of capital stock from occupied territories and shipping them back to the USSR itself is a way for them to rebuild.