This chapter of Raw to Ready: Mack Truck highlights how the trench warfare of WWI and the head wounds that killed thousands of soldiers led Sir Robert Hadfield, an English metallurgist, to experiment with alloys to strengthen the brittle steel helmets of the Allied forces. The tests with manganese created an alloy with the ability to form without fracture and absorb kinetic energy. The new helmets saved countless lives and helped win the war. Today the same alloy is used in the immense steel rails that are the backbone of the Mack Truck.