It's a world war one era "Regio Esercito" (Italian army) uniform like the ones you can see here.
the ranks on the cuff confirm the WW1 era (by design) and indicate the rank of Major, confirming this we have the jacket with pockets that was supplied only to the officers as the troops were without them.
Rank of WW1 Italian Army (In Italian)
If this is the relevant person:
(click to enlarge pictures)
then the actual salient points are:
cap: 'flying/winged wheels', double cockade -> Reichsbahn employee
shoulderboards to be expected as usual rank insignia: later than this timeframe, thus absent in this picture
before 1935: rank & section/specialty on display in gorget patches
What is ...
This is a Railway (Reichsbahn) uniform from the period 1924 until June 1935.
The rank is probably Rangieraufseher (Shunting supervisor).
Railway Cap, 1924-1935-06
Rangabzeichen nach der Dienstkleiderordnung (DKO) 1924
DPSG Kluft 1930-1939
May be the symbol seen on the 2nd person from ...
It is not an Imperial, Weimar, or Third Reich naval uniform.
It does, however, appear to be a Weimar period reichsbahn (railroad) police uniform . . .
Some discussion in a collectors' forum here
https://www.warrelics.eu/forum/weimar-soft-headgear/reichsbahn-headgear-368798/ several shots of this type uniform on the second page of the discussion thread.