Read Chapter 28: The Signal

The fluorescent strips overhead flickered in a dying rhythm, each pulse weaker than the last. Patel knelt by the open access panel in the baggage car floor, his torch wedged between his teeth, fingers working through a nest of cables that had been chewed by forty years of rats and neglect.

“There,” he said, spitting the torch into his palm. “Backup feeder line. Runs the length of the train. Independent of the main battery bank.”

Élise crouched beside him, her knees protesting. “Independent how?”

“It’s wired to the emergency lighting system on the surface side of the tunnel.” He traced the cable with a grubby fingernail. “If I can tap into it, we might be able to push a signal back up the line. It’s copper, not fiber, and it’s old. But a simple analogue burst could travel.”

“Travel to who?”

“Rail control. Emergency services. Anyone listening on the maintenance frequency.” He looked up at her, sweat beading on his forehead despite the cold. “It’s a one-way street though. The line only carries outgoing fault telemetry. We can transmit, but we can’t receive.”

From the doorway, Antoine’s voice came low and hoarse. “Then we don’t know if anyone’s hearing us.”

“We send blind,” Patel said. “We hammer the same code until we run out of power or they respond through another channel.”

Élise stood, steadying herself on the luggage rack as the train shuddered faintly. “What about the PA system?”

Patel blinked. “The what?”

“The passenger address system. It runs on its own circuit, doesn’t it? Separate speakers in every carriage.”

“Yes, but it’s not wired to the outside.”

“No,” she said. “But sound carries through rock. If we make enough noise, seismic sensors on the surface might pick it up. They use them to monitor tunnel integrity. A repetitive, low-frequency pulse could be read as an anomaly.”

Patel’s face changed slowly, calculation replacing exhaustion. “A coded thump pattern. The TGV’s PA system can push a bass-heavy signal through the carriage speakers. If I reroute the backup feeder into the amplifier cores, we could generate a pulse strong enough to resonate through the tunnel lining.”

“How loud?” Antoine asked.

“Painful,” Patel admitted. “Permanent hearing damage if you’re in the same carriage. But the passengers can move toward the rear. There’s enough distance.”

Élise nodded. “Do it. Antoine, help me move everyone to the last three carriages.”

The next forty minutes were a blur of shuffling bodies, muttered complaints, and the smell of fear. Passengers dragged blankets and bags toward the rear of the train, their faces pale and drawn under the failing lights. Clara was carried by her mother, her small body limp, her breath ragged and wet. Élise caught Antoine’s eye as they passed, and he gave a barely perceptible shake of his head.

No improvement.

Élise helped where she could, then made her way back to the baggage car. Patel had rigged a tangle of cables from the access panel to the PA amplifier bank, a Frankenstein construction of exposed wire and stripped insulation. He held a small handheld recorder in one hand, thumb hovering over a button.

“I’ve programmed a repeating sequence,” he said. “Three shorts, three longs, three shorts. SOS in Morse. At a frequency that should punch through.”

The amplifier bank hummed to life, a low growl that vibrated in Élise’s chest. Patel pressed the button.

The first pulse hit her like a punch to the sternum. A deep, thudding boom that she felt in her teeth. The carriage walls shook. Dust sifted from the ceiling panels.

Boom. Boom. Boom. Pause. Boom-boom-boom-boom-boom.

The sound was obscene in the enclosed space, a heartbeat made of pure force. Élise pressed her hands over her ears, but the vibration travelled through her skull, rattling her vision. Patel held his position, jaw clenched, watching a crude oscilloscope he’d attached to the feeder line.

After three minutes, he cut the power. The silence that followed was deafening, a ringing absence that hurt worse than the noise.

“No response,” he said, his voice flat. “But the line’s still live. The signal’s going out.”

“We try again,” Élise said. “Variations. Lower frequency. Maybe the amplitude needs adjusting.”

Patel nodded and began twisting dials.

They tried six more variations over the next two hours. Each burst drained the backup feeder’s remaining charge, the light in the carriage dimming further with every attempt. Passengers huddled in the rear, some weeping, most silent. The air grew thicker, metallic, recycled too many times.

On the seventh attempt, Patel froze mid-cycle. “Wait.”

The oscilloscope’s trace had jumped—a spike that wasn’t their signal. A patterned echo. Three shorts. Three longs. Three shorts.

“That’s not reflection,” he whispered. “That’s a reply.”

Élise’s heart seized. “From where?”

Patel adjusted the gain, his hands shaking. The trace spiked again, clearer now. A stronger signal bleeding through the line.

“It’s coming from the surface. They’ve rerouted a responder onto the same feeder. They’re acknowledging.”

The words had barely left his mouth when a voice crackled through a small speaker he’d jury-rigged to the circuit—tinny, distant, but unmistakably human.

“—peat. Channel Tunnel maintenance control to unidentified source. We read you. Repeat, we read you. Identify yourself.”

Patel grabbed the microphone. “This is the Paris-London express. Train 9174. We’re trapped inside. Repeat, we are trapped inside the tunnel. Do you copy?”

A pause stretched like wire. Then the voice returned, stronger.

“We copy, 9174. We’ve been searching for you for three days. Satellite trackers lost you at the French entrance. We assumed the worst.”

Élise took the microphone from Patel’s trembling hands. “This is Dr. Élise Fournier. We have survivors. Sick passengers. We urgently need extraction.”

“Stand by, Dr. Fournier.”

The silence that followed was worse than the noise had been. Élise could hear her own pulse in her ears, faster than it had any right to be. Beside her, Patel watched the oscilloscope trace, his jaw tight.

The voice returned, but it was different. Flatter. More careful.

“Dr. Fournier, we have your position triangulated. But I’m afraid we have some constraints on our end. A full extraction team can’t reach the portal for at least twenty hours. Bureaucratic hurdles. Safety protocols. You understand.”

Élise’s blood turned to ice. “Twenty hours. We don’t have fresh air for twenty hours.”

“Then I suggest you conserve what you have. We’ll be there as quickly as we can.”

The line went dead.

Patel stared at the speaker. “They cut us off.”

“They knew exactly where we were,” Élise said slowly. “They knew we were on that train. And they didn’t seem surprised to hear from us.”

Antoine had appeared in the doorway, his face shadowed. “What are you saying?”

“I’m saying the person on the other end of that line knew more than they should.” She set the microphone down, her hand steady despite the trembling in her gut. “Twenty hours isn’t a rescue timeline. It’s a delay. Someone doesn’t want us out of this tunnel before we run out of time.”

The lights in the carriage flickered once, twice, and then held—dim, but alive.

Alive for now.