It's not a loco, but loco may be seen here (7)
I believe the answer is:
station
'loco may be seen here' is the definition.
The answer is a location as well as being a singular noun. This is suggested by the definition.
'it's not a loco' is the wordplay.
'it's not a' can be anagrammed to 'STATION'.
Though, I am unsure how the anagram is indicated.
'but' acts as a link.
Can you help me to learn more?
(Other definitions for station that I've seen before include "Place - railway stop - HQ - standing" , "camp?" , "Stopping-place" , "Waterloo perhaps" , "Put" .)