Leo should have stopped. But he was a Ghost Listener. He wanted the truth of the defect.

The first minute was pure gold: the clank of a stoker, the hiss of superheated steam, the rhythmic chuff-chuff-chuff of a 4-8-8-4 Big Boy at full tilt. Then came the first defect—a skip that repeated the sound of a pressure gauge pegging past red. But instead of just repeating, the sound bent . The air in his shack grew thick, smelling of coal smoke and hot oil.

At 2:33, the world outside his shack went silent. No wind. No distant salvage rigs. Then, from his speakers, came a new sound: a rhythmic, metallic thud growing louder, like a giant’s heartbeat. The floorboards vibrated. His slate’s screen flickered, showing a waveform that was impossibly vertical—pure, infinite amplitude.