The first segment of the Kharkiv Metro system was built in relatively difficult hydrogeological situations. Specifically, engineers had to construct the line under two local rivers, the Kharkiv and the Lopan, and under two high traffic rail road stations, Kharkiv-Passenger and Kharkiv-Balashovskyi, respectively. Despite these difficulties, the first segment of the Kholodnohirsko–Zavodska line was finished relatively quickly, and was ready for its grand opening on August 23, 1975. The Kholodnohirsko–Zavodska line would be extended just three years later to encompass a total of 13 stations and of running track.