Pipelines (more commonly referred to as pipes) are a nigh-impassable terrain that are used by Black Hole for carrying materials.
In-depth[edit | edit source]
Pipes give no terrain stars.
Pipes serve a critical role in Black Hole's invasion of Macro Land in Advance Wars 2: Black Hole Rising. They are used for transporting materials between Black Hole's four factories and their main headquarters. In order to put them out of commission, the Allied Nations attacked the pipe seam nearest each pipe, rendering the factories useless. The pipe seams had similar defensive strength to a Medium Tank, but since they are wrapped in Lash's "Lash Armor" they take no damage from Missile Silos.
In Advance Wars: Dual Strike, it is not made clear whether or not pipes fulfill the same role as they did in the Macro Land invasion. Since the destruction of a pipe seam seemed trivial, they probably didn't. However, they did serve a new purpose - to act as a sort of track for Piperunners.
When a pipe seam is destroyed, the space where the seam once was is turned into a plains tile, but the gap in the pipe is clearly visible.