What were used to crush barbed wire and cross trenches in World War 1?
Tanks which appeared midway through the war. Even the heaviest artillery barrages (including shrapnel) were ineffective at cutting wire,as the British found on the first day of the Somme.
Tanks sometimes - but they appear very late in the war. Before (or if there were none handy) shrapnell shells were used to cut posts and wire, failing that - engineer/sappers crawled out to cut it at night.
