By October the Allied Hundred Days Offensive was in full swing, and the 8th Division participated in the forcing of the Rouvroy–Fresnes Line (7–8 October). The pioneers' role was to follow the division and improve the roads around Fresnes, many of which were damaged by delayed-action mines. The Germans began to retreat from their positions on 18 October, and the pursuit through Lens and Douai was slowed by road and bridge demolitions that the pioneers had to repair, sometimes under shell or machine-gun fire. Booby traps also caused casualties and work for the pioneers. 8th Division was relieved on the night of 4/5 November, and the Armistice with Germany came into force on 11 November, while the battalion was marching into Tournai behind the front-line troops.