Guo Zhihong, a train attendant, topped China's trending topics this week for her extraordinary knowledge of the national railway system.

She successfully drew a map of the national railway system, featuring 807 stations and 343 lines, within 90 minutes.

Guo is considered a "real map" who can offer the best traveling solutions to passengers when they encounter problems on the train. 

Memorizing the railway system was one of the skills tested in Guo's company in 2013, but she struggled to make progress at first. 

Drawing a railway map requires a good memory, as well as accurate calculation of the length between each station. One mistake could mean failing the task.

To learn to draw the map with the right measurements and names, Guo purchased 500 pieces of paper and practiced for at least five hours after work. She divided the railway system into four different parts, and memorized each of them.

The practice lasted for at least three years.

Why? She is the best "intelligence map," offering the quickest traveling solutions to passengers. For those who miss a station or take the wrong train, Guo can give a quick and time-saving plan.

Guo is not the only person to master the skill. In northern China's Jilin Province, a train ticket seller named Zhang Tong is also reported to be able to draw the 807 stations within 90 minutes.

"When and where to take the train are the questions people asked me the most," Zhang said. "Remembering the timetable and railway map is an essential skill for me to offer better service."

"They are excellent examples of what we can achieve in each job position," praised user@Jingyou on Chinese social media platform Weibo.

"My uncle had a similar test when he applied to be a taxi driver in Beijing," commented user@Mufengruyin on Weibo. "He was required to draw out the details of each valley and identical buildings around the city."