Construction of the Trans-Alaska Pipeline System for a fifth, should it become necessary. Holding tanks were planned that had a capacity equal to that of the pipeline, allowing the whole pipeline to be emptied if required. As required by the Pipeline Authorization Act, a ballast-water filtration system had to be designed as well. This system removes oil from tankers' ballast water so it is not released into Prince William Sound—something fishermen feared when the pipeline was proposed. Shortly after the permit was signed, convoys of equipment on snow tractors began heading north, using hardened snow roads and an ice bridge over the Yukon River to reach
Transalpine Pipeline It could be used to reverse the southern branch of the Druzhba pipeline to supply Slovakia. In Würmlach, Austria, the Adria-Wien Pipeline (AWP) branches off from the Transalpine Pipeline. It supplies the OMV refinery in Schwechat. Through the proposed Bratislava - Schwechat Pipeline it may supply also Slovakia. In addition to the sea transport, the Pan-European Pipeline, if constructed, will supply the Transalpine Pipeline. The diameter of the trunkline between Trieste and Ingolstadt is . Both sections starting from Ingolstadt are with in diameter. The pipeline has ten pumping stations. The pipeline system includes tank farms in Trieste and Lenting,