Originally Posted by
Koby
Picking up the ticket should be enough. On my last trip of this kind I didn't show my ticket to anyone on any of the two train legs.
The check-in agent most certainly did ask to see my stamped ticket when I did this, and the conductor on the train specifically asked if anyone needed it stamped. I wouldn't risk it.
Also you need to pick up the ticket in the train station so since you're already there you may as well take the train…