Pipeline transport of hydrocarbons detect the moisture accumulation location along the pipeline and increase effectiveness of the drying process. Drying air moisture content reduction is obtained by the installing additional intermediate air drying devices in by-pass lines at block valve station along the pipeline to be dried. Purging is proceeded until normalized dew point temperature value of the outcoming air being achieved. Purging is interrupted for 12 hours or more, both upstream and downstream ends of pipeline leaving hermetically closed, and resumed with intermediate air drying devices disabled, continuously measuring the moisture content of the outcoming drying air, fixing the moment when the moisture accumulation in the surrounding air.