lol! My husband works in road construction- I've seen this picture before with a line about how great John Deere machines are : )
Those are Excavators, modified to have the knitting needles instead of the scoop on the end.
It takes a very skilled operator (or in this case pair of operators) to manuver those machines well but they really are agile enough for that.
I was just loking at the site, and it looks like there was a guy on a "cherry picker" helping the process along.
OMG that is too clever! What's the yarn? It doesn't exactly look like laceweight
It doesn't say anywhere!! I kind of looks like fabric of some sort.