If it's anything like the factories I've worked in, you worked your butt off if you were on the assembly line. Material handlers had to hustle as well. The machine shop was a little more laid back. You probably never or rarely got to see the finished product you made parts for or assembled unless you were in final assembly, final inspection, or packing.
When they pinstriped the fenders they set the fender on a jig that looked like a bike wheel. They kept their hand steady on a rest with the brush and moved the fender on the jig as the paint was being applied. I think there is a youtube video of a bike factory in operation showing this but I don't think it was Schwinn. Gary