Well, why doesn't someone do something I haven't? :-)
Although I can spell pway and 12foot, S&T is not my specialism, but getting back to the map...

Searching for `PZB` gives Swedish Railways and...
https://wiki.openstreetmap.org/wiki/OpenRailwayMap/Tagging#Train_protection_systems
which links to
https://en.wikipedia.org/wiki/Punktf%C3%B6rmige_Zugbeeinflussung

Those look like unusual balaises.