The troops were eager for an opportunity to retaliate on the foe for trapping their comrades in the salient, and on November 14, 1917, a patrol succeeded in exacting a partial revenge. Assisted by some French troops they planned a night ambuscade near the German lines on a shell-ruined farm. It was a dreary vigil in the mud, where they lay throughout the small hours, until their patience was rewarded by the appearance of a large German patrol, in number more than double those of the Franco-Americans. They permitted the Germans to pass, and then attacked them on their flank. The fusillade of French and American bullets from shell craters and other shelters where the sharpshooters lay concealed took the Germans by surprise. They precipitately fled, taking their fallen with them. No French or American trooper was hit by the shots the Germans fired in their hurried retreat. More notable than such skirmishes on the American front before Lorraine was the part a number of unarmed American engineers, in company with Canadians, took in the encircling movement the Germans made on the British positions before Cambrai on November 30, 1917. For some time past American engineers had not only been of yeoman service behind the French lines in hauling tons of ammunition and other equipment to supply the French forces, but had been engaged on the railroad in the rear of the British front. They did not belong to the fighting units, and no achievements were looked for from men whose sole arms were picks and shovels. But the ramifications of the German assault on Gouzeaucourt brought these workers in the rear to the forefront of the attack, and they distinguished themselves in a manner which drew tributes from both the French and British high commands. A staid official account of the rôle they played thus describes the situation: "Two and one-half companies of railway engineers, with a strength of eight officers and 365 men, were encamped at Fins on November 30, 1917, having completed their work in the neighborhood. At 6.30 four officers and 280 men went to Gouzeaucourt, arriving at 7 and starting to work with Canadian engineers. The entire contingent was under a Canadian major and an American captain. The area was three miles in the rear of the line and none of the troops was armed. "At 7.15 German barrage fire moved on Gouzeaucourt after heavy shelling to the east. At 7.30 a general retirement was ordered, and it was effected with some difficulty, due to the artillery, machine-gun and airplane fire. "A number of losses were sustained at this time, and also among the men who, cut off by the German advance, had taken refuge in dugouts. Some of these men who had been cut off succeeded in joining British combatant units and fought with them during the day."