The telegraph lines from the Oryn Estuary had been buzzing for hours with a single, repeating emergency code: SOVEREIGN INBOUND. UNCHEDULED. FULL TENDER.
The Imperial Sovereign was no longer the clumsy peacock Deacon had seen in Solstice. The "Poisoned Blueprint" he had planted—the deliberate expansion-lag in the boiler tubes—had been compensated for by the Empire's brute-force solution: they had reinforced the hull with thick plates of lead-dampened steel and were running it on a high-grade alchemical coal that burned with a terrifying, white-hot intensity.
"It's not just an engine anymore, David," Miller said, his telescope fixed on the southern horizon. "The carriages behind it... they're encased in boiler-plate. Slotted for riflemen. It's an armored column on rails. They're using the Oakhaven Standard to bypass our mountain defenses."
Deacon stood on the platform of the Oakhaven Central Station. The "Logistical Insight" was running through a thousand permutations of disaster. If he blew the bridge at the Cleft, he destroyed the lifeline of the valley. If he met them with the militia, the Sun-Guard's superior numbers and the Sovereign's steam-cannons would turn the station into a slaughterhouse.
"We aren't going to fight the train," Deacon said, his voice dropping to a low, cold vibration. "We're going to use the Friction of the Standard."
He turned to the master of the shunting yard. "Clear the sidings at Mile Marker 10. I want the Variable-Gauge Switch engaged. And Miller, I need the high-pressure lubricant from the precision-lathes. All of it."
The "gritty realism" of the plan was a gamble on the very measurements Deacon had forced the Empire to adopt. The Imperial engineers had built the Sovereign to the Oakhaven Standard—4 feet, 8.5 inches—but they had built it with "Imperial Tolerance," a slightly looser fit to account for their inferior casting techniques.
As the Sovereign thundered into the valley, its whistle a screaming defiance of Oakhaven's sovereignty, Deacon's crew was at work on the tracks. They weren't pulling rails; they were "shimming" them. By inserting thin steel plates between the rail and the sleeper, they subtly narrowed the gauge by a mere quarter of an inch over a hundred-yard stretch.
"It's not enough to stop a wagon," Miller panted, pouring buckets of high-viscosity lathe oil over the narrowed rails. "But for an engine that heavy, running at that speed..."
"It's enough to turn the Standard into a vice," Deacon replied.
The Sovereign hit the "Vice-Section" at sixty miles per hour. To the soldiers inside the armored carriages, it felt like a sudden, jarring vibration. To the engine, it was a catastrophe of physics. The Imperial wheels, designed with just enough "play" to survive the Southern tracks, found themselves squeezed by the narrowed Oakhaven steel. The friction generated was instantaneous and immense.
The lathe oil, hit by the heat of the friction, didn't just lubricate; it vaporized, creating a cloud of blue smoke that blinded the Imperial driver. The Sovereign's massive driving wheels began to grind against the rail-heads, the lead-dampened steel screaming as it was literally planed away by the harder Oakhaven iron.
"She's seizing!" Miller shouted.
The Sovereign didn't derail. That would have been too merciful. Instead, the narrowed gauge and the lack of traction caused the engine to "bind." The massive kinetic energy of the armored carriages behind it slammed into the tender, the buffers shattering with the sound of a cannon-blast. The train ground to a shuddering, screeching halt, trapped in a trap of its own dimensions.
Deacon walked out onto the tracks as the steam cleared. The Sovereign was a wreck of buckled plates and glowing-red axles. The Sun-Guard scrambled out of the armored carriages, their rifles ready, but they found themselves surrounded by the Oakhaven militia—not with muskets, but with high-pressure steam-hoses and the "Vapor-Gonnes" mounted on the station roof.
"The track is Oakhaven property, Captain," Deacon said, stepping toward the lead carriage. "And your engine is currently in violation of our safety tolerances. You are under 'Administrative Detention' for the endangerment of the Permanent Way."
The Lord High Steward stepped out from the last carriage. He wasn't wearing armor; he was wearing the black-and-silver of the Imperial Court, but his face was a mask of cold fury. He looked at the smoking wheels of the Sovereign, then at Deacon.
"You've ruined the Emperor's finest machine, Cassian," the Steward said.
"I've enforced the Standard," Deacon countered. "You tried to use my logic to invade my home. But you forgot that a Standard only works if you respect the measurements. You built your 'Shadow-Rail' with Imperial pride, but the mountain only listens to the math."
The "Trojan Horse" had been neutered by a quarter-inch of steel. The Empire had the men and the powder, but Oakhaven held the "Key" to the rails. The Steward was forced to sign a "Reparations Agreement" on the spot—not for the lives of the soldiers, but for the damage his "illegal gauge" had caused to the Oakhaven tracks.
As the broken Sovereign was towed into the Oakhaven yard for "repairs"—which Deacon intended to stretch out for months—the valley breathed a collective sigh of relief. They had won the hundredth chapter of their survival.
"The Empire won't come back with a train next time, David," Julian said, looking at the captured engine. "They'll come with a siege-fleet."
"Let them," Deacon said, his hand resting on the cooling iron of the Sovereign. "By the time they build a fleet, we'll have the first Internal Combustion Engine ready for the 'Vindicator.' The age of the rail is just the beginning. We're going to take the Standard to the sky."