Hello; Before watching this video I had no idea that I wanted these machines. I suspect the very first video was a redo of them breaking through the tunnel, first because the circle of dirt where it broke out looked like it had been put back in and packed, and also, how come the tracks that the tunneling machine rode on were already laid through and out the hole where it broke out at? This was probably done so that the brass could be there for the breakthrough, and they could have a photo-op. Very interesting video. For those who see this kind of video for the first time, the video brings a lot of different meanings. This video is filled with a variety of knowledge and perspectives.