to meet daily needs and a large number of extra trains to transport heavy artillery ammunition. Until mid-June, ammunition supply for the BEF needed per week, then rose to |45 to 90 trains per week, to deliver a stock of of munitions. Ammunition expenditure became a concern by 12 July but deliveries to the area behind the Fourth Army kept pace, although transport from railheads to the guns was not always maintained. In the weeks before 1 July, an extra seven trains a day were sufficient to deliver ammunition. In the rear of the Fourth Army, huge encampments were built for troops, horses, artillery and workshops, dumps were filled with equipment, reservoirs and pipelines; power stations, light railways roads and telephone networks were constructed. Over of petrol per month was needed for the lorry fleet, moving supplies up to from railheads to the front line and a million Brodie helmets were delivered between January and June. In the 37th Division area, were needed to dig of trenches, jumping-off points, command-posts, dug-outs, machine-gun emplacements and ammunition stores, for wiring and for maintenance. In the French Sixth Army sector, one railway line from Amiens led to Bray on the north bank but on the south bank there were no rail lines; road-trains carried supplies from Amiens to Foucaucourt. Intelligence In March and April, eight German divisions were believed to be in reserve opposite the British from the Somme to the North Sea coast. Divisions in reserve behind the 4th Army were then moved south to Artois in the 6th Army area. From 4 to 14 June, the success of the Brusilov Offensive became apparent and agent reports showed increased railway movement from Belgium to Germany. The final BEF military intelligence estimate before 1 July had battalions opposite the Fourth Army and in reserve or close enough to reach the battlefield in the first week. Five of the seven German divisions in reserve had been engaged at Verdun and some divisions had been transferred from France to the Eastern Front. Men of the 1916 conscription class were appearing among German prisoners of war, suggesting that the German army had been weakened and that the British could break down the German front line and force a battle of manoeuvre on the defenders. In late June, the British part of the Somme plan was amended, rapidly to capture Bapaume and envelop the German defences northwards