Cooling Systems
The radiator assembly design in most rail stop shops dates to 2150. The markup does not. This is a solved problem. The part that isn't solved is getting one when you need it.
Technical Brief
Cooling units manage the heat generated by the crawler's drive motor and power cell bay. A radiator assembly and forced-air circulation loop keep both within operating parameters. By every engineering standard, this problem was solved before the Cascade. The thermal management principles in current aftermarket units trace to 2150s designs. Nothing about the technology has changed.
Ironclad Industries manufactures approximately 74% of cooling components available in Dregs-accessible shops. The units are adequate. Suggested retail on a replacement radiator assembly: 620 credits. Actual price in Sector 12's deep tunnel stretch, where the nearest competing vendor is eleven stops away: 1,380 credits. (Ironclad does not set regional pricing. Regional pricing sets itself.)
Nobody has filed a formal complaint. Filing a complaint requires reaching a terminal. Reaching a terminal requires a functioning crawler. A functioning crawler requires a cooling unit.
Thermal Behavior in Underground Sections
The tunnels trap heat. Ambient temperatures in poorly ventilated stretches exceed surface levels by 8–15 degrees, and the crawler's own waste heat has nowhere to dissipate. The Breath's atmospheric processing does not extend meaningfully into the deep rail tunnels. Air moves down there — slowly, and it arrives warm.
The fan pitch is the diagnostic. A steady hum is normal. A rising whine means the system is working harder than it should be. The distance between "working harder" and "not working" is shorter than anyone comfortable has measured, and it shrinks in direct proportion to tunnel depth. Spare cooling units rank alongside water and emergency power cells in standard runner loadout guides. Overheating in a tunnel is not a mechanical inconvenience. It is motor seizure, followed by power cell thermal runaway, followed by rupture and fire in an enclosed space with limited ventilation and no rapid exit.
The Neon Rail forums maintain a crowdsourced thermal map — tunnel sections color-coded by ambient temperature, annotated with fan-pitch thresholds and shop locations that stock cooling components. The map is updated by runners who survived the sections they're annotating. Sections with no annotations are either cool enough to be unremarkable or hot enough that nobody came back to post. The map does not distinguish between the two.
Implications
Runners in deep tunnel sections opt into a simple arrangement: pay the markup, or risk the alternative. The alternative ends careers. An entire logistical economy operates on the assumption that a runner deep in a poorly ventilated section will pay whatever price the nearest shop has set, because they will. Nobody is forced. The tunnel does the forcing.
Ironclad does not route runners into dangerous sections. The Sprawl's layout does that. Ironclad simply operates supply chains that terminate where desperation is highest, at margins calibrated accordingly. The consequence for runners who cannot afford a replacement unit mid-run is not a policy outcome. It is a thermal cascade event in an underground corridor, which is a different kind of outcome, but not a policy one.
What Nobody Can Explain
The crowdsourced thermal map has three red-flagged sections in Sector 12's deep stretch that no runner has annotated with shop proximity data — meaning either there are no shops within reachable distance, or the runners who found shops there did not return to post the location. The map's contributors do not agree on which interpretation is correct. They do agree the sections should be avoided.
Ironclad's 74% aftermarket share figure appears in Neon Rail forum posts, runner guides, and at least one Sprawl market analysis from a source nobody has been able to trace back to an original publication. The number is cited everywhere. Nobody knows where it came from first. (It may be accurate. Accuracy is not the interesting question.)