2 sets of 4 320x320 (width x height) "Sewer" arches
Each set contains:
- 1 end cap (pipe / bars)
- 1 straight
- 1 90 degree corner
- 1 T-Intersection

The full-circle arches fit a payload cart snuggly in the center trench
(tested, since I used this prefab for some early / unreleased iterations of pl_campania)

320x320 is a little tight so I may add other shapes and sizes in future