Sound travels faster than light down here, because there is no light. So we navigate by echo, and we move by thunder.
TECHNICAL MANUAL — Tube Network Operations WRITTEN BY: Lina Russo, Slingshot Operator, Third Class (she will not let you forget the Third Class part; she earned it) INTENDED AUDIENCE: New operators, curious civilians, and anyone who thinks the Tube is "just a train" WARNING: The Tube is not a train. Trains have schedules. The Tube has intentions. The Tube is the circulatory system of Toledo Underground. Seventeen contrade, spread across a cavern network that stretches 400 kilometres from Profondo in the deep south to Vetta in the north (Vetta is only 200 metres below the surface; the residents consider this dangerously exposed and the rest of us consider them slightly mad). Between these contrade, carved into the limestone by a combination of pre-Subsidence mining tunnels, natural fissures, and fifty years of determined engineering, runs the Tube: a network of electromagnetic rails that fire cargo pods at speeds up to 200 kilometres per hour. The Slingshot — that's what we call the l...
From the lore of Speranza.