That's correct though Germany, Austria and Switzerland run on 16.7 Hz where Sweden and Norway run on 16 and two thirds Hz
Would not be at all surprised to find that 16.7 is a misprint or a rounding up of 16.666... Hz ie 16+2/3rd's
No, the German (and adjacent countries) rail electrification system is actually 16.7 Hz.
It was previously 16 2/3 Hz (one third of the normal grid frequency) but the frequency was changed to 16.7 Hz in the 1990s to eliminate DC interference coming through.
Missed out on the Puttgarden-Rodby rail ferry last year because it was not running and there was only bustitution instead. So went the longer way from Hamburg to Copenhagen instead. The ferry must be a bit of a problem if they want to get rid of it entirely.
The ferry service has now permanently terminated, to make way for the tunnel construction.