A South Korean train heads North, but sanctions mean it has to carry its own fuel
https://edition.cnn.com/2018/11/29/asia/north-south-korea-train-intl/
It's meaningful for starting freight service between S.Korea and N.Korea or China.
But, even after fixing North Korean rails, it would be difficult to operate many trains for passengers moving between China and S.Korea.
That's because curve sections on the western line will restrict train speed, and then would be much slower than airplanes.
The best way to operate passenger trains is to build passenger dedicated lines where trains run at more than 300km/h.
It will enable trains connect Chinese border city of Dandong and S.Korean capital of Seoul within 2 hours.
