Description appears to be wrong
This page currently says that railway=yard is used to tag "a freight station", like railway=station but that appears to be wrong. It actually looks like these nodes are used to map rail yards (https://en.wikipedia.org/wiki/Rail_yard), as one might expect from the name. See for example https://www.openstreetmap.org/node/4448207661, https://www.openstreetmap.org/node/6111660864, https://www.openstreetmap.org/node/7489901802, and https://www.openstreetmap.org/node/7143779867
So I am going to re-write the page.