The functional infrastructure elements offer both a `designator` and a `typeDesignator`, where the `designator` is an identifier belonging to the individual object, and `typeDesignator` is an identifier of the type of object. In both cases, the identifier shall be listed in a register referenced by the `register` or `rulebook` attributes respectively. Some other railML elements don't describe an individual object, but a type. For consistency, these should not have `designator`, but `typeDesignator`. This also applies to elements with other names, but typed as `Designator`. Specifically `profile` and `steelGrade` in `Rail`, `CheckRail` and `Frog`. Related links: - Pointed out by Mathias in the forum: https://www.railml.org/forum/index.php?t=msg&th=1163&start=0& - Affects the documentation issue #777 - Applies to new `designator`s in #640