[moe]

If you click on "Fernverkehr" you'll notice that actually only 90% of intercity-trains have been within the 15min window.

Every 10th train was late for more than >15min.

Yes, Regios may be better. That doesn't help when, for example, you need to catch a plane in a different city.

[arrrg]

One in ten seems pretty good to me. Everything else are completely unrealistic expectations.