Abstract: A tunnel digging apparatus has an undercarriage pivotally attached to a moving means, the undercarriage being pivotable between a first moving position where the machine may be moved over a surface by operation of the moving means and a second operating position such that at least a portion of the undercarriage is in contact with the surface. The machine in the operating position is supported by at least a portion of the moving means and the portion of the undercarriage in contact with the surface.