Trench digging type i have seen before but tunneling ones i have not. Unless of course it is for rescuing earthquake victims of which Japan have alot of earthquakes. But that is mainly for rescue and not really for war fighting operations.Originally posted by equlus84:I have seen somewhere before that there is a Soviet era trench digging machine. It helps to dig rapidly a depth of abt 1m, for those FOFO type of operation.