| Lower Underrail|
|Major location information|
GMS warehouse block
Warehouse Block Alpha
Warehouse Block Beta
Hecate Research Outpost
|NPCs||Blaine, Jack Quicksilver|
Some caves are higher up and directly connected to Lower Underrail, these are known as Upper Caves.
Also immediately below Lower Underrail are under-passages, a network of smaller service tunnels and escape routes.
The Lower Underrail was the industrial/military zone of the big underground metro system before things went to hell. It consists of sprawling main tunnels, metro tunnels and beneath them are smaller escape routes and other accessways. Various stations, towns, other settlements, abandoned complexes and industrial facilities reside in the Lower Underrail. Some wall breaches also lead to adjoining Upper Caves.
Lower Underrail is accessible from South Gate Station level 1 exit. Most of the explorable areas are to the north from SGS, but there are a couple of areas to the south, including a wall breach leading to upper caves. However, most of Lower Underrail is initially inaccessible due to cave-ins caused by the recent earthquake. They can be visited later on, once the south metro tunnel is cleared and the player has access to TNT Charges.
Rathounds are a common sight and various, usually hostile, human outcasts have small camps all over the Lower Underrail.
- Ironhead Grenadiers (lvl10), Ironhead Gunners (lvl10), Ironhead Smashers (lvl10), Ironhead Psionics (lvl15)
- Lunatic Brawlers (lvl10), Lunatic Chillers (lvl10), Lunatic Gunners (lvl10), Lunatic Pyromaniacs (lvl15)
- Lurker Cut-Throats (lvl10), Lurker Gunners (lvl10), Lurker Gunslingers (lvl15), Lurker Hunters (lvl15), Lurker Murderers (lvl15)
- Other humans
- Bandits (during Jack's delivery job quest), Free Drones bandits (during lost train quest)
These areas of Lower Underrail lie to the south of Core City. These Lower Underrail tunnels make up a major part of South Underrail.
Near South Gate Station
Areas 5, 6, 7 and 8 east of South Gate Station are initially inaccessible, but can be explored once the player can clear the rocks blocking the way with TNT Charges.
Lower Underrail A4, connects to Upper Caves
Lower Underrail A7, connects to Upper Caves
Lower Underrail C11, Omega Station
Near Rail Crossing
Lower Underrail B8, connects to Under-passages
Lower Underrail B10, connects to Under-passages (hidden footlocker at the south end)
Lower Underrail B11, connects to Rail Crossing
Lower Underrail B13, connects to Abandoned Warehouse
Secluded Station (Lower Underrail B29)
Lower Underrail B30, outside South Railroad Outpost
Lower Underrail B14 ("How to tame a rathound" book)
Lower Underrail B16, connects to Warehouse Block Beta
Lower Underrail B19, Ironhead checkpoint, connects to Warehouse Block Beta
Lower Underrail B21, connects to Upper Caves
North of Foundry
Lower Underrail C1, connects to RAF 013