Encouraged by the capture of an armoured train at Chieveley, Joubert advanced south in two bodies, one on each side of Estcourt, and seized the railway at Highlands, thus cutting off Hildyard's communication with Pietermaritzburg; and Hildyard having no cavalry was unable to touch him. The raid, which for a time seemed dangerous, was however soon checked by troops coming up from the south under Barton, and Joubert found himself pressed between two forces each as strong as his own. After an action at Willow Grange, which each side claimed as a victory, Joubert, fearing lest he should be cut off, retired unpursued, against the wishes of the more pushful and energetic Botha, who was in favour of an advance on Pietermaritzburg. The alarms and excursions of October and November were the cause of the dissolution of a military apparatus which had been put together at home with much care and thought, and which had never yet been seen in warfare. Its designers and constructors were proud of it and they looked forward with confidence to its successful working. The apparatus was the British Army Corps. It was taken to pieces as soon as it reached South Africa; but fortunately the ties, ligaments, and braces which held it together yielded to slight pressure and little difficulty was experienced in resolving it into its constituent elements. The more important of these were despatched to Natal and the rest were distributed over the western and central commands. Buller, perhaps leaving the pessimistic atmosphere of Capetown with relief, went by sea to Durban, the defence of which was entrusted to the Royal Navy, and reached Pietermaritzburg on November 25. By this time the situation had improved all along the line, and it seemed that it might still be possible to resume the original plan of a central advance on Bloemfontein and Pretoria as soon as Ladysmith was relieved. The Boer raid towards southern Natal which caused so much consternation had been easily foiled and British troops were now at Frere. Buller, soon after his arrival in Natal, found himself in command of a force of 19,000 men with whom to tackle about 21,000 Boers under the command of L. Botha. Joubert was invalided after the unsuccessful Estcourt raid, and the change was, from the enemy's point of view, for the better. The new Head Commandant was a more strenuous and active leader than his predecessor. Little was known of the topography of the country in which Buller was about to operate. It had never been systematically surveyed, and the existing maps had been constructed for agricultural rather than for campaigning purposes, and could not be trusted. The Tugela formed the ditch of a natural fortress covering Ladysmith. On its left bank rose an almost continuous ridge or rampart from which the easy open ground on the right bank could be watched for miles, and reconnaissances kept at a distance.