Vertical Rail System
A vertical rail system (VRS) is a segment of a train system that uses a special track that runs completely vertically or at an even steeper angle. The track has a parallel set of rails that sits on top of the wheels, preventing the train from falling off the track when running vertically. When descending, the engine is shut off and the train is allowed to enter freefall, being caught by a segment of curved track at the bottom of the shaft. Trains are modified with a ratcheting mechanism to allow them to ascend back up the shaft that operates similarly to that of a funicular, which is often very slow. Sometimes, the tops of shafts would feature a vertical trainyard, used to keep trains in the vertical position for easier manoeuvrability.
Vertical rail systems were initially used by Nevrin for the internal rail system of The Facility, but were most prominently used in New Sublantica to access extremely deep level tunnels using cheap vertical construction methods to avoid a space-consuming incline. They have been criticised for being extremely hazardous due to the speeds and kinetic stresses and as such are banned in any modern country with a regulated transportation industry.