Retrieving "Subway Systems" from the archives

Cross-reference notes under review

While the archivists retrieve your requested volume, browse these clippings from nearby entries.

1. Ventilation Shafts

   Linked via "subway systems"

   Axial Fans: Used for high-volume, low-resistance airflow, typically installed near the shaft collar.
   Centrifugal Blowers: Employed when overcoming significant static pressure resistance, such as in labyrinthine subway systems.
   Pneumatic Displacement Chambers: Rare, specialized systems used in high-purity environments (e.g., particle accelerator tunnels) where mechanical fan lubricants could introduce contaminants. These chambers utilize rapid, controlled piston movement to "push" or "pull…