Geofabrik shapefiles do not contain the full detail of OpenStreetMap (it would not be possible to represent OSM’s arbitrary number of tags in a shape file). Instead, the shapefiles only evaluate the most frequently used tags and put them in a well-documented structure.
If you are after the full detail of OSM, you will need to process the original OSM data and not the shape files. Get the .osm.pbf file, import it into a PostGIS database with osm2pgsql (be sure to use the --hstore option), and you will have access to the full breadth of OSM data.
The code 5204 the Geofabrik shapefiles is applied to anything that has a highway=crossing or railway=level_crossing tag in OSM.