The Natal Railway Pioneer Staff advanced with General Buller and worked the Netherlands Railway as far as Greylingstad, 100 miles beyond Charlestown (the point of traffic exchange with the Transvaal system), until the line was taken over by the Imperial authorities on August 15, 1900. "For nearly six months, up to the relief of Ladysmith," says Mr. C. W. Francis Harrison, from whose official work on "Natal"[43] these details are mainly taken, "the Natal lines were robbed of about 40 per cent. of their total mileage and a quantity of their stock. On the clearance of the enemy from Natal and the south-eastern portion of the Transvaal, large supply depôts were formed at Newcastle, Volksrust, Standerton and intermediate points; and on the joining of the two main portions of the British army at Heidelberg, the greater portion of the stores for the forces was conveyed via Natal; and this continued unceasingly until the termination of hostilities." ARMOURED TRAINS It was, again, in the South African war that armoured trains underwent their greatest development--down to that time--for the purposes alike of line protection and of attack on the enemy, although their real usefulness and the conditions necessary to their efficient operation were not established until after certain early experiences which had tended to throw doubts upon their efficiency, and had even led to their being regarded as of little or no account for the purposes of war. In view of prospective requirements, five armoured trains had been constructed in advance in the locomotive shops at Cape Town and another at Natal. Others were put together shortly afterwards; but one of the Cape trains was wrecked by the Boers the first night of the war, and two of the Natal trains were locked up in Ladysmith. The remainder were employed on scouting expeditions during the earlier phases of the war. Their use not being then rightly understood, they were often sent considerable distances without any support, with the result that one of the Natal trains was destroyed by the Boers at Chieveley, on November 15, 1899, and the Cape trains had several narrow escapes of sharing the same fate. On the occupation of Bloemfontein by the British, more armoured trains were constructed at the railway workshops there, and eventually the number available was increased to a fleet of twenty. Under an improved system of control and operation, and converted, by the addition of guns, into what were virtually batteries on wheels, the trains came to be regarded as offering possibilities of much practical usefulness. In a lecture on "Railways in War," delivered by him at the Royal Engineers' Institute, Chatham, and reported in the "Royal Engineers Journal" for July, 1905, Sir Percy Girouard, said:--