The single worst thing about most of these clips is the person holding the camera. It would be nice if someone knew how to film without shaking the camera all the time.If there's a way to describe heavy machines, it's the silent giants of progress, shaping the world with every move.Thank you for uploading and sharing this well researched and well documented video. By watching videos such as this on YouTube one learn a lot from the comfort of our homes. Well done ! Keep recording and uploading and sharing videos like this !