One of the most popular rail routes is the one from Seoul to Busan. The most popular fast trains are called KTX and KTX Sancheon which are operated by Korail.
most popular rail routes Korean Bullet trains
As a rule, there are 10 or 20 train cars forming the train set as well as several coach classes to choose from: 2nd Class (Standard) usually has seats arranged 2 by 2, whereas the KTX