The Third Rail is a toll gang of about twenty-five members that controls access to Chicago's abandoned CTA tunnel system. The trains stopped running decades ago, but the tunnels remain — miles of underground corridors connecting neighborhoods that are otherwise separated by surface-level gang territories, flooded streets, and Axiom checkpoints. For people who need to move through the city without being seen, the old subway tunnels are the best option. The Third Rail charges for access.

The crew maintains three main access points — sealed CTA stations that they've reopened and fortified — and patrols a network of tunnels that stretches from the Loop south to 95th Street. They've mapped the entire system, identifying which tunnels are passable, which are flooded, which have collapsed, and which connect to other underground infrastructure like utility tunnels and basement networks. This map is their most valuable asset and they guard it with lethal force.

The Third Rail's tolls are modest for foot traffic — enough to fund the crew and maintain the tunnels. Vehicle access (where tunnel dimensions allow modified low-profile vehicles) costs significantly more. Smuggling runs, where the crew provides guides and guarantees safe passage, are priced at premium rates. The most expensive service is emergency extraction: if you're on the surface and every exit is closed, the Third Rail can get you underground and moving within minutes, for a price that reflects your desperation.

The tunnels are also the Third Rail's defense. They know every junction, every dead end, every flood point, and every emergency exit. Anyone who tries to take the tunnels from them enters a three-dimensional maze where the defenders have total knowledge and the attackers have none. Two larger gangs have tried to seize the system. Both were led into dead-end tunnels and dealt with there.