You might have to switch to, say, a JR train line. But that’s not a function of the paper tickets. Just different lines. Honestly the much crazier thing is that

You might have to switch to, say, a JR train line. But that’s not a function of the paper tickets. Just different lines. Honestly the much crazier thing is that some trains go over tracks of different companies because they simply cooperate for the benefit of the consumer. You mostly don’t need to know whose line it is ever. The niche exception is for tourists with a JR Pass.