About three weeks before, the siege-train for which General Wilson had been for weeks anxiously waiting, left Firozpur. It stretched for five miles along the Great Trunk Road, and was furnished with an inconsiderable escort. On the twenty-fourth of August, General Wilson learnt that a large force of rebels, with sixteen guns, had left Delhi for Najafgarh, with the object of intercepting the siege-train and cutting off supplies from the Ridge. Nicholson, ever eager for active work, was given the task of dealing with the mutineers. Early on the morning of August 25, in pouring rain, Nicholson left camp at the head of two thousand five hundred men, consisting of horse and foot, British and native, and three troops of horse artillery under Major Tombs. To their great delight, Sherdil and Ahmed were among the squadron of Guides that formed part of the force. The march reminded them of the former expedition to Alipur. For nine miles they struggled through swamp and quagmire, the mud so deep that the guns often sank up to the axles and stuck fast, the rain falling in torrents all the time. Some of the artillery officers despaired of getting their guns through, but when they saw Nicholson's great form riding steadily on as if nothing was the matter, they took courage, feeling sure that all was right. A short halt was made at the village of Nanghir, and while the troops were resting, two officers rode forward to reconnoitre a nullah that crossed the road about five miles away. They found that a crossing was practicable, and from its bank they descried the enemy's outposts. It was five o'clock before the column had forded the nullah, under fire of the rebels. Darkness would soon fall, and if the enemy was to be routed no time could be lost. Nicholson himself rode forward to reconnoitre their position. It extended for two miles, from the town of Najafgarh on the left to the bridge over the Najafgarh canal on the right. The strongest point was an old serai at their left centre, where they had four guns; nine other guns lay between this and the bridge. This serai he resolved to attack with his infantry, the guns covering the flanks, and the 9th Lancers and Guides to support the line. As soon as the line was formed, Nicholson ordered the infantry to lie down while the guns made an attempt to silence those of the enemy. He rode along the line, addressing each regiment in turn, aptly suiting his words to what he knew of their previous achievements in war. One order he gave to them all: to reserve their fire until they came within forty yards of the serai, then to pour in one volley and charge home.