A Note with a Boundary

The eastern ledge held Mercy’s engine, but it did not hold still.

Oliver felt the shift through the soles of his boots as the rail settled against its catches. He watched the wheels for another movement, then crouched beside the forward axle. The joint had taken the load. The hoist cable behind them hung slack and twisted, its last use finished. There was no emergency coupling pin left to improvise with if another part failed.

Nadia stood at the ledge’s outer edge, one hand on the rail. Below her, the floating fragment’s underside fell away into cloud. “It’s holding,” she said.

“For now.” Oliver rose. “I want a walking inspection before we put the engine under power again.”

She gave him a look. “Then walk.”

They left Mercy’s controls and followed the old iron route ahead, keeping one hand on the fixed safety line. The rails climbed a shallow curve around the fragment’s shoulder. Rust filmed them, but the fastenings were intact. Beyond the bend, the track vanished behind a shelf of stone.

Oliver stopped when a note sounded from the far side.

The lower whistle.

It came once, cleanly, and carried across the ledge without the wobble of an echo. Nadia’s fingers tightened on the rail. Oliver listened for a second note and heard only the little clicks of cooling metal behind them.

“You could answer,” Nadia said.

“I could.”

“Would that tell us anything?”

“Only that someone might answer back.” He looked toward the bend. “And I don’t know what they’d think I’d promised.”

She didn’t argue. The train’s whistle sat in its bracket behind them, close enough for him to reach. Instead, Oliver took a short length of loose rail from the tool rack and struck it once against the fixed track. The sound rang hard and ordinary. He waited.

Nothing answered.

“That was your answer?” Nadia asked.

“It was a noise.”

He set the rail down. Their boots carried them around the bend, where the route opened onto a narrow shelf cut into the fragment. A spur branched away from the main iron line, running to a squat signal hut attached to the rock. The spur had no proper platform. Its outer rail ended in empty air, and a cable as thick as Oliver’s wrist ran from the hut to a ring set in the cliff.

A figure stood inside the hut’s open doorway.

The person held a brass whistle in one hand. It was longer than Mercy’s, with a dark wooden mouthpiece and a band of worn lettering around its center. The figure kept the whistle lowered.