With that, Bai Cheng also quickly got up and went to the front of the train, choosing to activate this Advancement mission.

As for the difficulty, she wasn't worried at all.

Based on the content of previous Advancement missions, the boss's strength was only Guardian Rank, which was child's play for the current Bai Cheng.

The screen began to display the current loot mission, and the train's trajectory subtly changed accordingly.

Then, Bai Cheng ordered Lan Xiaoyu to proceed at full speed; she wanted to unlock the final loot mission as quickly as possible.

This kind of loot mission was merely a prerequisite for starting the Advancement mission, posing no difficulty for Bai Cheng.

While the train sped through the sand sea, Bai Cheng didn't waste time. Instead, she first used a portion of the already smelted star diamond ore to upgrade the carriages.

There were simply too many materials. She still had two cores unused, and if she didn't quickly consume some of them, there really wouldn't be enough space.

As Bai Cheng clicked confirm on the screen, the familiar white light once again enveloped several carriages.

The light flashed by, and the upgrade was completed in an instant.

Bai Cheng curiously looked at the carriages to check the situation, only to see that their length and width had significantly increased, almost to 1.5 times their original size.

In addition to the spatial changes, the entire interior was covered with a deep orange interior made of various leathers, carpets, and gems, already showing signs of luxury.

Compared to before, the changes in the carriages upgraded with star diamond ore were undeniably significant.

Bai Cheng continued to look at the screen, checking the information.

【Name: #1/#2/#3... Carriages】

【Level: Lv.9 (max)...】

【Train Core Attributes: Wild Growth/Ultimate Ice Seal/Psionic Energy...】

【Your ordinary carriage level has been raised to the highest level, custom layout enabled!】

"As expected, it has reached max level." Bai Cheng showed no surprise, as she had long guessed that Lv.9 was the limit for carriage levels.

"It seems that after the train is upgraded, it will soon begin its advanced mission."

Bai Cheng pondered, and this also indicated that after they, the Survivors, entered the core area of this world, their development focus was no longer limited to building the train itself.

"But what does this custom layout... mean?"

"It can't be like stacking carriages like building blocks, can it?"

While the literal meaning wasn't hard to understand, applying it to carriages left Bai Cheng puzzled.

She continued to click to examine the changes in detail.

【You can now freely combine and arrange carriage positions. This is a completely free-willed process; build your train to your heart's content!】

(Note: Modifications can only be made within the Station.)

【Hint: If carriages are placed parallel or vertically, two Armored Cores will automatically merge into one and an extra door will appear. Of course, you can also choose not to set up isolation armor walls, or even use only half a carriage or suspend it...】

【As a reward for upgrading the carriage to the highest level, you have now obtained the Carriage Construction Blueprint.】

“...”

"Is that really it?!"

Looking at the long string of descriptions, Bai Cheng's face showed a mix of surprise and lack of surprise.

In short, the carriages could now truly be freely combined like building blocks, even allowing for a second floor or an extra-large bedroom.

None of this would affect the train's operation.

"If they were all stacked one on top of another, wouldn't the train turn into a steel behemoth?"

Bai Cheng seemed to realize the benefits of the custom layout. This would be a huge advantage whether facing ordinary trains or beast attacks.

At least she wouldn't have ❀ Nоvеlігht ❀ (Don’t copy, read here) to worry about the trouble of a train being too long to manage both ends.

Although this kind of thing was completely a weak point for Bai Cheng... "Xiaoyu, you saw all that, right?" She cast a look of heavy responsibility towards Lan Xiaoyu.

The latter nodded expressionlessly.

"Good, then the task of modifying the train is entrusted to you!" She solemnly patted the other's shoulder, "You still have time to conceptualize, no rush."

With that, Bai Cheng continued to use the Carriage Construction Blueprint.

【Name: Train Ordinary Carriage】

【Description: Can build a carriage, but you can still only add and modify it within the Station.】

【Construction Required: 1000 star diamond ore, 1000 magic crystals, 100 train cores】

【Evaluation: Finally, carriage freedom can be achieved!】

"Huh, it actually doesn't require smelted star diamond ore?" Bai Cheng was still a bit surprised by this.

However, custom layouts could only be done when entering a Station, which meant she couldn't build carriages right now.

Bai Cheng didn't pay too much attention to this; after all, it wasn't a critical matter for her.

It wasn't until evening that, upon completing the last loot mission, enough star diamond ore for upgrading the train head had finally been smelted.

Bai Cheng decisively upgraded the train head. She wanted to see what changes a max-level train head would bring.

As always, a white light appeared, and the interior of the cockpit instantly became as luxurious and dazzling as the max-level carriages.

Most importantly, the body armor had now turned a gleaming white, and even the Employee Watchtower on the roof had been reinforced.

At this moment, the entire train not only displayed a shimmering starlight white, but its body design was also an extremely perfect streamline.

The exterior balcony was removed, and the front plow for defense was gone, yet the overall defense was undoubtedly greatly increased compared to before.

Even the train doors became modern sliding doors.

But Bai Cheng didn't have time to notice these details; her gaze immediately went to the screen.

【Train: Steam Train】

【Level: Lv.9 (max)】

【Armored Core: Space Matrix】

【Maximum Connectable Carriages: 8】

【Max Speed: 150km/h】

【Employees: Scarlet Flame, Guardian Tier 2 / Purple Iris, Guardian Tier 2 / Lvdou, Guardian Tier 3 / Azure Bird, Guardian Tier 1 / Huang Yu, Guardian Tier 1 / Lan Xiaoyu, Guardian Tier 1】

【Installed Components: Employee Watchtower, powered railcar】

【Your Steam Train's level has reached its maximum limit, advanced mission activated!】

【Train Advancement Conditions: 0/500 Mechanical Parts, 0/50 Train Cores, 500 Magic Crystals, 0/1 Internal Combustion Engine】

"The speed directly increased by 20km/h this time." Bai Cheng keenly noticed this detail.

At the same time, a material she had never seen before appeared in the advanced mission.

"Mechanical Parts, what are those?" Bai Cheng raised an eyebrow, "And where am I supposed to get an Internal Combustion Engine, huh?!"

"Forget it, don't worry about those for now."

Bai Cheng didn't overthink it and closed the prompt after a glance.

Now that all prerequisite loot missions were complete, her Advancement mission was the first priority!

【Advancement Mission (3): Crown King】

【Mission Details: The Station has been fixed as a special Advancement Trial Station. Defeat the BOSS to obtain an Advancement slot.】

【Announcement: This Station is a free-type Station. All Survivors from other channels will receive a notification and can enter and exit without restrictions. You cannot invite Survivors from this channel who are not in the public area to assist you.】

【Cooldown: 5 days】

【Note: The number of Advancement slots you obtain will be fixed (slots depend on the number of occupants on the train).】

【Hint: This mission is quite difficult. It is recommended to be fully prepared before challenging it.】

Bai Cheng looked at the information before her and was slightly stunned. "What does this hint mean?"

In the past, when she activated Advancement missions, the system had never given any information about mission difficulty. Why was it specifically stated this time?

"Could it be telling me to find helpers?" She rolled her eyes. Those leaders were not even cannon fodder to her now.

Bai Cheng didn't care about this hint, because she was very sure that she was now fully prepared.

Bai Cheng gave an order.

"Depart for the Advancement Platform!"