The four-wheeled check car sat upon the strap-iron rails like a giant clockwork grasshopper.
It was framed in seasoned white ash, eight feet long and five feet wide. He carried a low platform of two-inch oak planks.
In the center of the chassis rose an iron A-frame supporting a four-foot wooden walking beam with twin crossbar handles, geared directly to the rear axle through a three-to-one bronze edge gear.
Four sixteen-inch cast-iron wheels rested upon the gleaming wrought-iron straps, their cone-shaped treads centered between the rails with an eighth of an inch of lateral play.
Giles Croft stood on the forward footboard. He held an open brass pocket stopwatch in his left hand and his wooden ruler tucked under his arm.
Beside him, two burly timberwrights took their places at opposite ends of the pump-lever. Their calloused hands gripped the ash handles.
“The clockwork advantage of the walking beam is four point two,” Giles instructed, adjusting his glasses against the sharp morning wind.
“At twenty double-strokes per minute, the gear ratio will produce an axle rotation of sixty turns a minute. On a sixteen-inch wheel, that translates to a working speed of fourteen point two miles per hour.”
Before boarding the footboard, Giles crouched beside the front axle with his oiler can, checking the bronze pillow-block bearings.
“Split bronze metal sleeves with an internal helical oil groove,” Giles noted. He pointed his rule at the machined casting. “When the axle rotates, the spiral groove draws beef animal fat from the central pool and distributes a nonstop water-flow fluid film across the journal.
If the bearing runs dry, friction will gall the bronze within three miles. Check the grease levels at every staging post, Toby.”
Toby nodded, jotting the upkeep interval on his slate. “Every three miles, Lord Giles! Three turns of the squeezing grease-cup!”
Master Caleb wiped sawdust from his beard with a grin.
“The car runs so smooth on the track that you could push it with one finger on a level grade. I never thought I’d see four tons of iron move without two pairs of oxen leaning into the yoke.”
Captain Kenneth Drake stepped onto the rear bumper, his hand resting firmly on the long ash lever of the friction brake.
The brake gearwork consisted of two curved blocks of seasoned beech-wood, shod with scrap leather, set directly above the rear wheel treads.
“I’ve ridden war-chariots in the southern border wars, my lord,” Kenneth said. He looked down the dead-straight line of rails stretching toward the riverport.
“When two tons of iron starts rolling on metal without horses, how do we stop it if the ditch curves?”
“The friction lever exerts a four-to-one clamping force against the wheel rim,” Giles explained.
“The multiplier of moving friction between dry beech-wood and cast iron is about point-three-five. At fifteen miles per hour, the car will slow down to a dead stop within forty-five paces without locking the wheels or skidding.”
Kenneth grunted, testing the spring of the brake lever with his boot. “Provided the wood doesn’t catch fire.”
“Beech-wood has a starting heat well above three hundred degrees,” Giles said. “If you smell smoke, apply the lever in pulses to allow heat-rising air cooling. Toby, sound the departure horn.”
Toby Karr stood on the track shoulder, blowing a long, clear note on a polished brass horn.
“Track is clear to Mile Marker Two!” Toby shouted, waving his red land-mapper’s flag.
“Start pumping,” Giles commanded.
The two timberwrights threw their weight onto the walking beam.
CLACK-CHUG. CLACK-CHUG.
The bronze edge gears meshed with a smooth, oiled hum.
The four cast-iron wheels began to turn.
For the first ten yards, the gaining speed was heavy and deliberate. Then, as the static heavy rush of the four-ton load was overcome, the rolling pushback dropped away like a cut lead weight.
The car surged forward.
Within thirty paces, the walking beam was rocking with an easy, rhythmic sweep.
The two timberwrights were no longer straining. They were merely following the motion of the handles, laughing in shock as the wind whipped their tunics.
CLACK. CLACK.
The sound of the flanged wheels crossing the mitered scarf joints of the iron straps was music to Giles’s ears. A crisp, metronomic percussion that echoed across the dry peat flats.
The scenery began to blur.
The willow stands along the canal bank swept past like green banners. The drainage ditch, which earlier took a laborer forty minutes of heavy walking to cross, was devoured beneath the wheels in seconds.
Kenneth Drake gripped the brake lever with white knuckles, his cloak streaming straight out behind him like a battle pennant.
“By the King’s blood,” Kenneth shouted over the rushing wind. “We’re flying! We’re outrunning a royal courier on a fresh horse!”
Giles looked down at his stopwatch, his thumb hovering over the split-second detent.
“Current speed is thirteen point eight miles per hour,” Giles noted calmly. “Wheel-hop is negligible.
The cone-shaped tread taper is holding the chassis centered within three-sixteenths of an inch of the track axis. Zero pipe rim hunting observed.”
Kenneth looked down at the four tons of iron metal bars resting in the central cradle, then back at the two men pumping the beam with easy grins.
“A single flatcar,” Kenneth breathed, his tactical mind racing with terrifying speed.
“We can mount twenty arbalestiers on a timber box car. We can move an entire company of heavy infantry from the central stronghold to any point along the southern frontier before an enemy raider can even string his bow.”
“You can move thirty tons of freight per day with two mules and three drivers,” Giles corrected.
“Or four hundred laborers to the peat cutting in twelve minutes flat. Military mobility is a backup bonus. The main objective is freight volume per man-hour.”
“It’s the same thing, my lord,” Kenneth said, a fierce grin splitting his scarred face. “In war, the man who brings thirty tons of iron to the fight first always wins.”
* * *
The car swept past Mile Marker One at eight minutes and twelve seconds.
Down at the river wharves, two miles away, a crowd of hundreds of settlers stood watching the miraculous machine hurtle across the Black Fen like a silver arrow.
Lady Millicent Croft stood on the warehouse platform with her pocket watch open, her face a mask of calm, triumphant arithmetic.
“Eight minutes,” Millicent noted to Master Duncan.
“The heavy cart wagons took three hours and forty minutes to haul that same load through the mud this morning. We have just removed ninety-four percent of our overland transit overhead.”
Duncan shook his head, leaning against his hammer. “The world is getting too fast, Lady Millicent. A man won’t even have time to finish his pipe between the forge and the wharf.”
Out on the tracks, the flatcar was approaching the gentle curve at Mile Marker Two.
Giles clicked his stopwatch. “Ten minutes and forty seconds. Prepare to reduce speed, Kenneth. Feather the brake lever.”
Kenneth pulled back on the ash handle.
The beech-wood blocks pressed down upon the revolving iron treads.
A clean, fragrant smell of heated wood and toasted oil rose from the wheels. The car slowed smoothly from fourteen miles per hour down to six.
Then, Kenneth’s eyes widened.
“Giles,” Kenneth barked, throwing his full weight onto the brake lever. “Look at the rail ahead!”
Fifty yards before the canal bridge, the gleaming silver line of the strap-iron track suddenly vanished.
Covering the timber stringers and spreading across the crushed granite ballast was a thick, waving carpet of velvet-black growth.
It wasn’t common moss or harmless swamp mold.
It was a pulsating, living mat of necro-fungal mycelium, three inches thick, covered in thousands of tiny, weeping black pustules that dripped a yellow, oily slime onto the iron plates.
Where the slime touched the iron straps, the metal was wildly corroding.
A sharp, hissing sizzle filled the air, with plumes of choking, acidic white smoke that smelled of rotting meat and battery acid.
The solid half-inch iron strap plates were dissolving before their eyes, eaten into spongy, ragged lace that flaked into orange rust.
“Brakes!” Giles ordered sharply. “Lock the wheels!”
Kenneth hauled the lever to the stops.
The beech blocks bit hard.
With a screech of iron on metal, the car skidded across the dry rails. That left two thin streaks of shaved iron before coming to a dead halt barely ten paces from the black fungal barrier.
Giles stepped off the footboard, his boots crunching on the ballast.
He walked to the edge of the growth, pulling his folding rule and crouching to inspect the damage.
The iron strap on the right rail was fully cut across a three-foot section.
The load-bearing oak stringer beneath it had softened into a black, spongy mush that crumbled into powder when prodded with the brass metal ring of his rule.
From deep within the black reeds of the canal marsh came a low, rasping hiss.
A dark figure stood fifty paces out in the stale water, draped in rotting reeds and bone necklaces. It held a staff crowned with a bleached hydra skull.
“The Iron Road dies,” a dry, croaking voice floated across the fen like a funeral chant. “Hesketh weaves the rot that eats the works of men.
Turn back, false builder... Or your bones shall feed the Black Mildew.”
Kenneth drew his broadsword with a ringing scrape of steel, stepping in front of Giles.
“Cultist,” Kenneth growled. “Give me thirty seconds and a javelin, my lord. I’ll pin his tongue to that willow.”
“Hold fire, Kenneth,” Giles said calmly, standing up and dusting his trousers.
He pulled a glass sample phial from his pocket, used a scrap of sheet iron to scrape a dollop of the hissing black slime into the tube. Then he stoppered it tight.
“A targeted living acid attack on load-bearing metalworking,” Giles noted with clean, steady care. “A fascinating bio-rusting vector.
But chemically primitive. Toby, send word to Sister Teresa. Tell her we need the high-pressure burning lime powder tanks, fifty gallons of sodium stone-glass, and every bag of borax in the storehouse.”
Mistress Pippa the Fermenter arrived from the survey camp. She held her wooden assay box and a strip of litmus parchment.
She dipped the paper into the bubbling slime on the ruined rail. The paper turned dark, angry scarlet within two seconds.
“Sulfuric acid combined with organic fungal toxins,” Pippa reported, her brow furrowed. “It’s the Rot-Cult’s black brew.
They feed it on decomposing marsh bog-iron and spoiled grain. It can dissolve an iron kettle in an hour, Lord Giles!”
“Then it has an acidic concentration of nearly three molar,” Giles observed calmly. “Standard heavy-duty rusting problem. Iron and steel can’t resist active sulfuric acid without offering coatings or glassy passivation.
Wood rots because the acid hydrolyzes the plant fiber polymers. But glassy heat-proof glass is fully chemically inert. It doesn’t react with sulfuric acid at any concentration.”
He turned back toward the stranded rail car.
“We have an acid-proof glassy glaze to invent.”