What does it mean for subway elderly people to look at their mobile phones?

It was an old man who squinted at his mobile phone while taking the subway, and then generated an expression pack. The old man watching the mobile phone in the subway is an expression pack, which shows the grandfather sitting on the subway, frowning and looking at the mobile phone in his hand. His expression is very exaggerated and confusing, expressing incomprehension, confusion and disgust. Subway is short for underground railway. It is an independent rail transit system, which is not affected by the ground road conditions, can operate normally according to the designed capacity, and transport passengers quickly, safely and comfortably.