I read some discussions in German.
It seems that "the first train" on a line is chosen, then the time which this train travels from station a to b is shown on journey time in station b.
I am not sure my understanding is right or not, and what is the definition of "the first train" on a line? Is "the first train" on a line varied with new trains on this line?
And I found that the journey time sometimes is changing.
Thanks a lot.