The immediate purpose of the expedition had thus been attained; but, in the meantime, a further campaign had been resolved upon for the purpose of breaking down the power of the Khalifa and effecting the conquest of Khartoum. To this end the railway was continued another hundred miles, from Kosha to Kerma, which point was reached in May, 1897. Some 216 miles of railway had thus been completed in about thirteen months, notwithstanding interruptions which had led to very little progress being made during five months of this period, and notwithstanding, also, the fact that construction work had to be carried on simultaneously with the transport of troops and stores so far as the line had been completed. Before, however, Kerma was reached, Sir Herbert Kitchener instructed the staff of the Royal Engineers to make a survey of the Nubian Desert with a view to seeing whether or not it would be practicable to build an alternative line of railway across it from Wady Halfa direct to Abu Hamed (a distance of 232 miles), thus giving a direct route to Khartoum. A survey carried out at the end of 1896 showed that the work was not likely to present any unsurmountable engineering difficulties, and that the absence of water could be overcome by the sinking of wells. The only doubtful point was whether construction could be carried through without interruption by a still active enemy. It was seen that the proposed desert line was likely to be of far greater importance, both strategically and politically, than a continuation of the Wady Halfa-Kerma line round the remainder of the Nile bend. The cutting off of this bend altogether would confer a great advantage on the Expeditionary Force. It was thus resolved to build the line, to run the risk of attacks by the enemy, and to push construction forward with the greatest energy.