Seoul metro Line 9 extended
https://www.metro-report.com/news/news-by-region/asia-pacific-ex-china/single-view/view/seoul-metro-line-9-extended.html
Seoul Metro Line 9 is famous for its crowded express trains. After the extension, it will be much more convenient to use Seoul Metro Line 9.
It means express trains will be much more crowded than ever since.
So, there will have to be more express trains on the subway line.
But, judging from its capacity, 8 express services per hour are the maximum frequency.
Otherwise, there will have to be much more siding tracks.
