The 50th Reserve Division was reinforced by one storm company of the 3rd Jäger Battalion, equipped with four machine guns, two trench-mortars and two field guns, with a further storm company of that battalion attached to 230th RIR for "certain enterprises" along the railway line. Between Dernancourt and Buire-sur-l'Ancre, the assault would be launched by the 13th Division, which would attack with all three regiments. On the right, the 15th Infantry Regiment (IR) was to attack the railway line held by the 52nd Battalion from the woods near Ville-sur-Ancre. In the centre, the 55th IR was to assault the line held by the 10th Brigade of the 3rd Division, between Treux and Marrett Wood. On the left, the 13th IR would also attack the 10th Brigade line south of Marrett Wood. Late in the evening of 4 April, a report was received, apparently from a reliable French spy, that converging attacks would be made on Amiens the following day, launched from Albert, and Roye further south. In response, Congreve ordered the field artillery of the 3rd and 4th Divisions, augmented by some heavy guns, to shell all likely assembly areas commencing at 07:30. If a German bombardment descended before that time, the British and Australian artillery were to direct their fire onto the German battery positions. The warning of the pending attack reached the brigade commanders of the 4th Division before midnight, and they ordered out special patrols to search for signs of assembling German troops. When the warning was received by Whitham, he immediately ordered his support company, under Captain Kennedy, to move from the valley north of Buire-sur-l'Ancre into the series of posts that ran through the CCS. He visited all three of his companies along the railway line and explained to each company commander that if they were driven from the front line, they were to withdraw to Kennedy's support line and make their last stand there. By the time Whitham returned to his headquarters, Kennedy's company had taken up its positions in the support line, although it was only occupying the posts west of the CCS. When the warning was received, a working party of the 4th Pioneer Battalion, numbering one officer and 27 men, were digging tunnels through the embankment in the right forward company sector of the 47th Battalion near the railway bridge. They stood to arms with the rest, reinforcing the two platoons nearest the railway bridge.