Pipeline transport in order to avoid melting the frozen ground by hot petroleum which would result in sinking the pipeline in the ground. Maintenance of pipelines includes checking cathodic protection levels for the proper range, surveillance for construction, erosion, or leaks by foot, land vehicle, boat, or air, and running cleaning pigs, when there is anything carried in the pipeline that is corrosive. US pipeline maintenance rules are covered in Code of Federal Regulations(CFR) sections, 49 CFR 192 for natural gas pipelines, and 49 CFR 195 for petroleum liquid pipelines. In the US, onshore and offshore pipelines used to transport oil and
Northern Lights (pipeline) by the Vukhtyl gas field, but later the pipeline was extended in order to connect with the Urengoy gas field. The Northern Lights pipeline system has a total length of , of which around is used to transport Russian gas to Europe. The pipeline runs from the Urengoy gas field through Vuktyl, Ukhta, Gryazovets, Torzhok and Smolensk to Minsk in Belarus and from there to Poland, Ukraine and Lithuania. A part of the newer Yamal–Europe pipeline runs parallel to the Northern Lights pipeline. A branch line from Gryazovets through Saint Petersburg to Vyborg supplies the Saint Petersburg area and Finland.