1927, steam shovel assisting in the excavation of a train tunnel... the photo says that it used compressed air instead of overheating the miners with making and releasing steam Automotive cool small steam shovel thoughhttp://www.blackdiamondnow.net/black-diamond-now/2014/02/one-last-post-about-the-great-northern-i-promise.html Automotive Email ThisBlogThis!Share to XShare to Facebook