Trench warfare
Trench warfare occurred when a revolution in firepower was not matched by similar advances in mobility, resulting in a grueling form of warfare in which the defender held the advantage. On the Western Front in 1914–1918, both sides constructed elaborate trench, underground, and dugout systems opposing each other along a front, protected from assault by barbed wire, mines, camouflaged trapping pits, and other obstacles. The area between opposing trench lines (known as "no man's land") was fully exposed to artillery fire from both sides. Attacks, even if successful, often sustained severe casualties.
Logistics in World War I
However, as the war ground down into static trench warfare it became easier for armies to support their troops with the use of the railway, especially for the artillery. This made the transportation of supplies easier and quicker to get from the factories to the front line. This did have problems of their own, as seen by the Shell Crisis of 1915. Where the stalemate of trench warfare took hold, special narrow gauge trench railways were built to extend the rail network to the front lines. The great size of the German Army proved too much for its railways to support except while immobile. Tactical successes like Operation Michael devolved into operational failures where logistics failed to keep up with the army's advance over shell-torn ground.