WW I "Gobron Subway, Vimy Ridge. Assembly position of 72nd Battalion,n CEF 9 April 1917. [Used in history facing page 44) Sign showing GOBRON SUBWAY. From the Regimental History (pages 44 - 48): "On that evening the Battalion moved into Gobron Tunnel on Vimy Ridge in readiness for the final attack. The culmination of months of tireless effort, of difficult raids and patrols was now in view. A winter spent under the most trying conditions was to show results. That the 72nd Battalion had paid the price was to be seen in the fact that wastage and casualties had so far reduced its numbers that 400 of all ranks was the total number assembled in the tunnel on that evening." Hot soup and other refreshments were supplied to the waiting men and were much appreciated. Zero hour was 5:30 a.m., when, in addition to a terrific artillery and machine gun barrage, two heavy mines were to be sprung under the enemy trenches opposite to the 72nd front. At about 5 a.m. on this Easter Monday, April 9th, the Battalion quitted Gobron Tunnel and filed into the assembly trenches. It was a most inclement morning of sleet and snow which the west wind fortunately drove into the faces of the foe. The Ridge itself, churned out of all semblance to its former self by the rain of shells it had received intermittently through the. winter, and without respite during the past ten days, seemed nothing but a vast expanse of small lakes formed by the linked-up shell-craters. Progress across this ground under the most favourable conditions would have demanded great exertion." For resupply, the communication trenches were too narrow and winding. The solution was to construct "subways". At Vimy there were 12 subway tunnel systems. They went from beneath the forward trenches to assist the forward flow of men and supplies in complete security. Varying in length from 250 metres to nearly two kms, the subways contained forward headquarters, communications nodes, forward supply dumps, assembly areas for infantry companies and advanced dressing stations. At between 5 and 15 metres deep, They were fairly protected. They were typically 2.25 metres high and about 1.25 metres wide. British Engineer tunneling companies dug the subways at Vimy as the Canadian engineers were in the Ypres Sector assisting the British.