This task is about reading the given passage and construct a question about the information present in the passage. Construct a question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) its answer is a continuous text span from the paragraph. Avoid creating questions that (i) can be answered correctly without actually understanding the paragraph and (ii) uses same words or phrases given in the passage.

Nanjing is an important railway hub in eastern China. It serves as rail junction for the Beijing-Shanghai (Jinghu) (which is itself composed of the old Jinpu and Huning Railways), Nanjing–Tongling Railway (Ningtong), Nanjing–Qidong (Ningqi), and the Nanjing-Xian (Ningxi) which encompasses the Hefei–Nanjing Railway. Nanjing is connected to the national high-speed railway network by Beijing–Shanghai High-Speed Railway and Shanghai–Wuhan–Chengdu Passenger Dedicated Line, with several more high-speed rail lines under construction.
Nanjing's railway is important, and is located in what region of China?