Currently downloading western section of gas transportation system of Ukraine decreased by 2,5 times compared to the project. This caused changes in the modes of pipelines, pressure fluctuations and gas consumption and, consequently, the number of changes in the system of gas pipelines. Therefore there is a need to study the mode of gas transportation system during underemployment. As a research facility selected western area of the gas transport system of Ukraine, the capacity of which reaches 111 billion. m3 / year of gas intended for export. CCS CONCEPTS: Computer System Organization → Dependable and Fault-Tolerant System and Networks → Maintainability and Maintenance. Keywords: Fatigue, Flood, Stress Concentrator, Welded Joint, Weld Seam, Gas Pipeline, Static Load, Low Frequency Load.