Naval department's daily tram trip (9)
I believe the answer is:
admiralty
'naval department's' is the definition.
'admiralty' can be an answer for 'department's' (admiralty is a kind of department). I am unsure of the 'naval' bit.
'daily tram trip' is the wordplay.
'trip' is an anagram indicator.
'daily'+'tram'='dailytram'
'dailytram' anagrammed gives 'ADMIRALTY'.
Can you help me to learn more?
(Other definitions for admiralty that I've seen before include "Former Department in charge of the navy in Britain" , "HQ" , "Department of 1 across in charge of the Navy" , "UK state department in charge of the Royal Navy" .)