"Tieling Wasteland" is a low-level area, where a maximum of level 3 trains can be accommodated, and only level 3 monsters may emerge. When the train reaches level 3 and is fully equipped, ready to advance to level 4, it needs to head to a higher-level domain and start preparing for a career change.
There are two career change options.
Mechanical Train, Flesh and Blood Train.
Each level-up introduces changes not only by increasing the train's basic speed and allowing for more buildable parts but also by adding one or more new functions with each level.
For example, the new function upon reaching level 2 is "Personalized Customization."
And the additional new function when reaching level 3 is—
"Heritage Value."
