WW1-era Pioniertruppe A7V-Schützengrabenbagger LMG trench digger of the German Army, c. 1918. Only one was produced.
https://s3-us-west-1.amazonaws.com/h...n_trencher.jpg
Previously:
https://www.homemadetools.net/forum/...110#post125894
https://www.homemadetools.net/forum/...491#post122730
https://www.homemadetools.net/forum/...017#post120191
https://www.homemadetools.net/forum/...993#post100437