At the moment of firing one of the great railway guns, the Germany gunners put their hands to their ears and open their mouths to relieve the pressure on their ear drums caused by the detonation. This picture gives an excellent view of the recoil jacks. One left centre and the other right. The growth of heavier defenses such as the maginot and siegfried lines have had their natural result in an increase in the size of offensive artillery. The German Army has developed a great railway gun which is an advance on anything known before. August 12, 1940. (Photo by Associated Press Photo).