That particular form is actually rather tricky. While it has ProdRoute in the data source, it is actually pulling data from Route and RouteOpr and combining them into ProdRoute, much in the same way that would happen during the creation of a production order. Then later when you save the data, it transfers your changes from ProdRoute back to Route and RouteOpr. The ProdRoute data source on that form is set to a temporary table in code.
To answer your question, a route is made of up the tables RouteTable (header) and Route (lines), just like a bill of material. Additional data (like process time, etc.) is stored in table RouteOpr in rule form, like trade agreements. The field RouteId is the relationship between RouteTable and Route. Then RouteVersion is used to associate a RouteTable record with an InventTable record, or a released product, using ItemId as the relationship. note that a single route can be associated with multiple released products. Also some of these records have from/to date fields and can be activated and approved.
Hope this helps.