You can use a Linear Assets Shell to keep track of linear assets such as roads, rails, pipelines, and power lines. Linear Assets are pre-designed Shell types that you can use to create Shells. Linear Assets are at the same level as Buildings, in the hierarchy, so when you create a Linear Assets Shell, Unifier places the Shell under the the Sites type Shells, similar to Buildings. The Shell Manager section of this guide provides more details about Linear Assets manager.