Hello,
Andy from OSM's Data Working Group here.  First things first, thanks to both of you for trying to have a sensible discussion here rather than than just reverting / unreverting.
However, a couple of things need to be made clear.  The first is that OpenStreetMap is a map of things that currently exist.  As old buildings are demolished and replaced with new ones, we don't keep the old buildings in OSM in perpetuity, we delete them.  The old data is still accessible of course - just do an overpass search on OSM data before the building was deleted.
Secondly, it's absolutely true that when railways stop being used as railways and the tracks are removed, some infrastructure often remains (bridges, embankments, etc.), and it's perfectly OK to map that remaining infrastructure as "railway=abandoned" or similar.  However, when there is really nothing left, it isn't OK to use that tag.  An example of where there appears to be nothing left (at least based on imagery) is just down the road from this changeset at https://www.openstreetmap.org/#map=19/50.766415/7.191619 .  It looks like railway=abandoned is not the right tag to use there.
It's correct to say that there have been a lot of forum discussions about mapping former railway lines where no trace exists on the ground.  However I think that there IS a clear majority that believes that "things that no longer exist and hence cannot be surveyed do not belong in OSM".  For completeness there's also a significant minority that believes that OSM should contain razed and unsurveyable railway infrastructure, and another significant minority that believes that something that is not in 2025 a railway should not be mapped with a "railway" tag.
People who like maps of no-longer-existing railways really do need to "read the room" a bit better and do what they can to get their contributions into OpenHistoricalMap, because it's pretty clear which way this is all going.  Another clear advantage of OpenHistoricalMap is the ability to add start and end dates for everything, something that isn't at all easy to do in OSM.
A challenge is the licence - OSM's licence doesn't match OHM's so the person who added the data to OSM needs to make clear what licences was used before it can be transferred.