Within nineteen months after the Turkish Government had issued its bonds to cover the cost of the project, the first section of the Bagdad Railway, from Konia to Bulgurlu, had been completed. The success of the concessionaires in this part of the enterprise might have been taken as a criterion of rapid progress with the further construction of the line to the Persian Gulf. Such an expectation, however, would have been premature. Beyond Bulgurlu lay the Taurus mountains and innumerable engineering difficulties which could be overcome only after the expenditure of considerable time and money. The Turkish Government, furthermore, was in no position to issue additional bonds to the amount of fifty or sixty millions francs to cover the costs of constructing the second section of the line. Interest and sinking fund charges on the first issue of Bagdad Railway bonds were a serious drain on the treasury; additional charges of a like character could be met only by an increase of the customs revenues of the Empire. Such an increase could not be effected, however, except by international agreement, because under existing treaties between Turkey and the Great Powers all import duties were fixed at eight per cent _ad valorem_.[10] In 1903, coincident with the first issue of bonds for the Bagdad Railway, the Ottoman Government had requested permission to increase these duties to eleven per cent but had been unable to obtain the consent of the interested nations. It was not until 1906, after prolonged and irritating negotiations, that the Powers agreed to a three per cent increase, effective in July of the following year. Even then, however, the higher duties were assented to under a number of restrictions which rendered difficult the diversion of the increased revenue to the payment of railway guarantees; elaborate regulations were incorporated in the treaties prescribing expensive reform of the government of Macedonia and costly readjustments in the customs administration.[11]