Apocalypse: I Built the Infinite Train

Inside the dark train carriage, the warmth from the heating system created a stark contrast to the freezing cold beyond the thick armor.

Lying on his bed, Lin Xian glanced at Chen Sixuan, who was sound asleep beside him, a hint of gratitude flickering in his eyes.

The apocalypse had taught him a lot in a short time.

Food and water were incredibly scarce, and while zombies and eerie entities were deadly threats, the isolation and fear of survival were just as suffocating.

Without Chen Sixuan’s support, without KIKI’s ability, without Luo Ye and Shasha’s help, even finding the courage to keep going would have been incredibly difficult.

Outside, the blizzard raged on. Lin Xian got up, dressed, and quietly made his way to the Whale 03E’s cockpit, activating his Mechanical Heart to run a full diagnostic and repair check on the train.

The massive eerie entity in the sky weighed on his mind like a dark cloud, keeping him restless. He decided to use the time to reinforce the train’s armor a little.

Now that the train’s armor had been upgraded, the increased weight—combined with the power consumption of the heating system—was putting a strain on the electric locomotive’s energy reserves. This directly increased the fuel cost of running the train.

"If I don’t upgrade my Mechanical Heart to Level 3, even traveling 300 km a day will be a struggle..."

After handling the most critical armor repairs, Lin Xian returned to bed, set an alarm, and forced himself to rest.

Thanks to the Soul Wave Detector, he only assigned Luo Ye to guard the rear of the train for the night. The radar warning system in the front car gave him some peace of mind. He needed to recover his energy—tomorrow wouldn’t be easy.

Beep beep. Beep beep.

At 8:00 AM, Lin Xian’s wristwatch alarm woke him up. He felt significantly recharged.

Chen Sixuan was still fast asleep—as one of the only two non-enhanced humans on board, her stamina was far lower than the others. Even compared to Shasha, she was physically weaker. After days of constant tension, this was probably the first time she’d had a proper rest.

Not wanting to disturb her, Lin Xian quietly got up, opened the door to Carriage No. 2, and found KIKI already sitting at the computer, hard at work.

"Hallo, boss!"

KIKI hadn’t turned on the overhead lights. The soft glow of the monitor illuminated her face, making Lin Xian suddenly think of a phrase—

“Internet-addicted girl.”

"...You’re up early?"

"I slept for so long, okay?" KIKI stretched lazily, full of energy, and grinned. "Right now, I’m the most awake person on this train."

"Not bad, Energetic Little Miss." Lin Xian smirked. "Are you working on the water-oxygen circulation system?"

"Here~"

KIKI pointed at the screen and pursed her lips.

"It’s not that simple. First, we need a separate storage tank for living water, separate from the train’s water supply. Then there’s the filtration system, which depends on what kind of purifier blueprint you plan to use."

"If you want to set up a heating system, you’ll need to link the train’s water tank and the living water tank into a loop. That way, you can integrate distillation—it purifies the water and provides heat at the same time."

"As for the water-oxygen system, that’s even trickier. If you’re setting up a planting carriage, you’ll need hydroponics, drip irrigation, and air regulation—meaning you’d have to fully seal the train to make the oxygen cycle work properly..."

Hearing this, Lin Xian got interested. He pulled up a chair and sat down.

"Right, originally, I just wanted to improve the train’s water supply, but now we have to consider purification, recycling, heating, and farming. It’s getting more complicated... but we can start with water purification and recycling first. Heating-wise, the current warm-air system is still functional."

"I was thinking—the Underground City No. 9 must have advanced systems in place. We can’t copy them directly, but we can study their design. Maybe they even have a ready-made system we can take advantage of..."

KIKI’s eyes lit up. "Oh! That’s right! A place that big definitely has a botanical zone! And a medical system!"

Clap!

She slapped her palms together, her gaze burning with excitement as she stared at Lin Xian.

"And one more critical thing!"

"What?"

"An AI system module!" KIKI’s eyes widened. "If we can get a high-performance AI, we can have it design a customized solution for our train’s systems! Way better than us brainstorming blindly!"

Lin Xian nodded. "That makes sense."

"And also, and also—" KIKI was getting more and more excited, spinning her chair around. Because she was only wearing shorts, her long legs stretched out carelessly toward Lin Xian.

"The underground city might even have an Eternal-Class Rail Train—used for resource transport or emergency evacuation."

"These super-trains have miniature nuclear reactors on board. If we could get our hands on one..."

Seeing her over-the-top enthusiasm, Lin Xian couldn’t help but smirk.

Of course, he wanted all these things. He knew the underground city would have cutting-edge tech. For someone with Mechanical Abilities, it was paradise.

But he also knew...

Things aren’t that simple.

First, the underground cities were federal government assets before the world fell apart. Did the new Apocalypse Union maintain them? Were they still operational?

Even if they were intact, an apocalypse-scale underground city would have insane security measures.

KIKI might be able to sneak in, but that didn’t mean he could.

And more importantly—

Time was running out.

Yubei City’s No. 1 Spaceport Passage would close in three days.

Even considering travel time, he had less than two days to explore the underground city.

But looking at KIKI’s beaming face, Lin Xian didn’t want to crush her enthusiasm just yet.

"If things go smoothly," he said, "our train might undergo a huge upgrade. Once we pass the High-Altitude Corridor, we’ll reach Jiazhou City in under a week. From there, it’s only a short trip to Jinhai."

The moment he said this, KIKI’s smile disappeared.

She stared at him sharply.

"Wait, what did you just say?"

"...What’s wrong?" Lin Xian frowned. Did he say something incorrect?

Thud! Thud! Thud!

Before he could react, KIKI suddenly jumped off her chair, barefoot, and ran up to him.

Like a cat, she straddled his lap, grabbed his shirt collar, and pulled him close, her eyes burning with anger.

"Jinhai? What, are you planning to kick me off the train again?!"

Lin Xian looked into her big, beautiful eyes and instantly understood.

He chuckled.

"How could I? You’re our communications expert. I was just talking about the route."

"Really...?"

KIKI stared intensely into his eyes, so close he could feel her breath on his face—

A soft, tingling sensation.

"Really." Lin Xian nodded seriously.

For a moment, the air went still.

Then, out of nowhere, KIKI lunged forward and bit his nose!

Chomp!

Then she shoved him away.

"Get lost, get lost! Don’t interrupt my work!"

Lin Xian touched his nose in shock.

What the hell was that move?!