So there you are at a main railway station.Just as
You are on the last minute to catch the train you want.
You check the departure screen to locate the correct platform and if the train is running on time.
Just as you are getting to the required point on the screen, it moves onto another page thus taking away the relevant information.
Then you have the choice, gamble that it will leave from the booked platform, or wait for the page to return after it has scrolled through a couple of pages of trains leaving in the distant future and some other irrelevant blurb, thereby running the risk of missing the train you want.