Maybe we have different definition of fewer trains, because I wouldn't expect more than 10% at most, realistically 2-3%. And those trains are probably already 2-3%.
Many international trains were actually not running. I haven't read up on the details yet as I was away this weekend, but I think it was only short cross-border routes that still worked, but not much more. The night trains only started up past midnight. And anyway, even if more than that had run, night trains and international trains only run on a small number of Dutch train routes. The three daytime long-distance international train routes are: Amsterdam-Rotterdam-Antwerpen and onwards, Amsterdam-Arnhem-Duisburg and onwards, Amsterdam-Hengelo-Osnabrück and onwards (several intermediate stations omitted). The only domestic night service is Utrecht-Amsterdam-The Hague-Rotterdam. That's it. You can't fit any serious amount of domestic travel into those more than they already normally carry.
