Interesting video. What amazes me is that you don't see anyone spiking down the rails before the work train rolls over them. I did catch sight of one guy bolting rails together ahead of the train, but with only two bolts, not four. The other two bolts were put in behind the work train, as well as most if not all of the spikes. Appears to be on the Grand Trunk Western RR, which would most likely place the filming location in Michigan.