Comment by Tade0

> SBB grants Eurocity trains on the Munich-Zurich route a buffer of ten minutes before reallocating their train path, and even 15 minutes for ICE trains between Freiburg and Basel.

Emphasis mine. This whole system works because they account for delays by having a time buffer in each route that can be consumed by going slower.

During my commutes along Lake Zurich I noticed that the trains would rarely arrive earlier than 30s before schedule - even if it meant going below the maximum allowed speed, as evidenced by instances where the train used the same section to restore the buffer by going faster.