- World Incredible Modern Construction Equipment Machines Technology - Biggest Heavy Equipment Machines Working

 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. Thanks for sharing!
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