The bumpiness on the lower bunk wasn't too noticeable, but once you got to the middle or upper bunk, it became far more obvious. Even a slight jolt of the train could wake up light sleepers.
Tang Yuxin wasn't a light sleeper, but she couldn't sleep in this environment. Even with no lights on, it wasn't possible for her to read. Phones at this time didn't have all the features they have now, so reading a book on her phone was out of the question. Moreover, she didn't like to read on her phone. As a doctor, her eyes were very important, so she would never do something that could harm them.
She rested her head on her suitcase, which was too hard and too high. No matter how she adjusted herself, she just couldn't get comfortable. On the other hand, the person on the top bunk was sleeping soundly, as she could hear their snores.