I didn't realize that Swiss trains apparently also adhere to the "schedule for 80% of capacity rule".
Apparently trains in Switzerland go around 80% of the top speed possible on the track. The 20% overhead is used to make up time in the case of delays.
The thinking is: stable and predictable operation is more important than going faster. Because the cost of passengers regularly missing layovers is much higher than the benefits of trains being 20% faster.

miki
in reply to yosh • • •How does this work when a delayed train is behind a non-delayed one on the track?
I feel like introducing a rule like this would require us[1] to redesign our train infrastructure to enable more points where trains can overtake eachother.
[1] Where "us" can mean whatever you want it to mean, and the point will still stand.
Andre Videla
in reply to miki • • •@miki this scenario rarely happens on Swiss rail. The manjority of routes are "monotonic", that is, a train ahead in schedule will also be ahead In arrival time. This is due to at least three factors:
There are scenarios where it happens, those are when regional trains interact with intercity trains. In that case, a track change is made to allow the intercity trains to pass a regional train at a station, but those cases are the other way around: the regional train is delayed such that the intercity unexpectedly caught up.
What's key here is that it's not necessarily a product of infrastructure and more a result of careful planing and inter-operator cooperation.
miki
in reply to Andre Videla • • •@Andrev Ah, that makes sense.
As far as I know, what we do in Poland is quite the opposite. If a train is delayed, we allow that single train to be delayed more and more, to keep the rest of the schedule intact. This prevents a single delay from affecting the entire system.