Thanks for the reply. It seems that we have different understandings of what railway=abandoned means.
The way I am interpreting the wiki and have used it is that it doesen't mean "former railway" but instead "former railway still traceable".

Not everyone needs to be able to immediatly trace it from the ground - but it should be possible, and it is the case here. 

The embarkments, tree lines, buildings alignments, railtrails, etc etc etc and heck, even the difference in vegetation color on farmland are still remnants that actually exist on the ground. Those features didn't just came out of nowhere - they're only there because there is/was a railroad right-of-way. 
I don't see anything wrong with mapping that context, especially in times where micromapping like 3Dbuildings, manholes, road markings, parking spaces. etc is encouraged.