Impresit’s fifth lot was in the south, where the train was to wind its way through the mountainous province of Khuzestan. The remoteness of the location made it difficult to maintain supply lines. In summer, temperatures reached such scorching levels that work was conducted at night. Apart from the dozen engineers, 20 administrative officers and 80 technicians, there were 12,000 locals - all working uninterruptedly for 26 months.