Krupp's K5 series were consistent in mounting a 21.5-metre-long (71 ft) gun barrel in a fixed mounting with only adjustable vertical elevation of the weapon. This gondola was then mounted on a pair of 12-wheel bogies designed to be operated on commercial and military rails built to German standards. This mounting permitted only two degrees of horizontal traverse. The carriage had to be aligned on the rails first, with only minimal fine leveling capable once halted. Hence the gun could only fire at targets tangential to an existing railway track.