OSM doesn't enter overweight, difficult relations representing continent-wide planning corridors, which are actually multiple-corridor and contain spurs.

OSM does make route=railway relations, sometimes at a (rail-)company-wide level, sometimes at a country-wide level.

Accordingly, I'm about to break apart this almost 19000 member beast into at least five pieces, per country.  The proposed and construction elements will be deleted.  Still, some child relations will still contain thousands of elements and must be broken up further.  I may not have the local / rail company knowledge required to further subdivide accurately, I attempt to simply make the data manageable given current tools and platforms.