Found this video of mainline steam in the Netherlands -- from last month -- mostly running at about 60 mph.
https://www.youtube.com/watch?v=60qbNb2lozo
It's a little over an hour, but well worth watching as it shows the run from two engine-mounted cameras and from some lineside photographers, too.
The run includes some interesting Netherlands trackage, including through some some of the Netherlands' long underwater tunnels, over some long bridges, and through several large stations.
While I am not an expert on the Netherlands railways by any means, I may be able to answer some questions about this video, if you have any.
Enjoy,
-- Ernest