The Subterranean Foundry was producing iron at a rate that far exceeded the capacity of manual haulage. To keep the furnaces fed and the residential tiers expanding, Kael needed to move tons of ore, flux, and stone through the mountain's arteries every hour. The existing manual carts, pushed by teams of Tier 0 laborers, were a logistical bottleneck. To reach the manganese deposits two miles to the east without alerting any remaining Imperial patrols on the surface, Kael initiated the Deep-Rail—the barony's first automated, subterranean transport system.
The technical foundation was the stationary steam-winch. Instead of putting an engine on every car, Kael utilized the mountain's geothermal surplus to power massive, rotating drums at the terminal ends of the main shafts. A continuous loop of braided iron cable, coated in a thick layer of protective grease, ran the length of the tunnels. The ore cars were equipped with a mechanical "Grip-Jaw" that allowed them to latch onto the moving cable and be pulled along the rails at a steady, relentless pace.
The grit of the construction involved the precision of the rail-beds. Unlike surface tracks, which could expand and contract with the weather, the subterranean rails were bolted directly into the limestone bedrock. Kael utilized a laser-leveling system—a simple but effective tool consisting of a concentrated beam of light from a bioluminescent algae-vial directed through a series of pinhole shutters. This ensured that the two-mile line remained perfectly straight, minimizing the friction that would otherwise snap the iron cables.
Socially, the Deep-Rail redefined the geography of the mountain. The "Central Hub" became the new social anchor, a place where the residential tiers met the industrial arteries. The new Aspirants, particularly those with experience in Imperial logistics, were placed in charge of the "Switching Yards"—complex junctions where cars were diverted to different levels of the mine. This required a high degree of mathematical coordination, further integrating the former soldiers into the barony's intellectual fabric.
A mechanical failure occurred during the first high-load test. The friction of the iron cable against the guide rollers in a sharp curve near the east-ridge began to generate enough heat to ignite the grease. A thick, acrid smoke began to fill the transport tunnel, threatening to overwhelm the ventilation scrubbers.
Kael utilized the Roller-Cooling Bypass. He tapped into the aqueduct's secondary return line, running a thin copper pipe alongside the cable guide-rollers. Small apertures in the pipe dripped cold river water directly onto the rollers, providing constant evaporative cooling and lubrication. The "hiss" of the water hitting the hot rollers became the characteristic sound of the Deep-Rail's curves.
The engineering of the "Deep-Rail" allowed for the population to expand into the "East Reach" vaults. As the rail reached the manganese deposit, Kael ordered the construction of Tier 6 Residential—a specialized district for the miners and rail-engineers. The population count rose to 745 as the first group of families from the surrounding Salt-Spur foothills, hearing rumors of the mountain's stability and warmth, sought refuge at the intake gate.
Kael stood at the Central Hub, watching a string of ten ore cars glide silently past, their "Grip-Jaws" locked firmly onto the iron cable. The mountain was no longer just a fortress; it was becoming a network.
The East Reach is open, Elms, Kael said, noting the steady flow of manganese into the foundry bins. We have the transport and we have the materials. But a network this size is vulnerable to "Vibration-Echoes." If Vane's engineers are still on the surface with their own seismic tools, they'll be able to map our every tunnel by the sound of these cars. We need to start the Sonic-Damping project. We need to wrap our rails in a way that makes the mountain sound silent to those above.
Kael began sketching the designs for the first composite rail-ties—a mixture of compressed peat-fiber and rubberized sap designed to swallow the mechanical noise of the deep-rail.