Port newly built alongside railway (7)
I believe the answer is:
tilbury
'port' is the definition.
Both the answer and definition are singular nouns.
Perhaps you can see an association between them that I don't see?
'newly built alongside railway' is the wordplay.
'newly' is an anagram indicator.
'alongside' means one lot of letters go next to another.
'railway' becomes 'ry' (abbreviation for railway).
'built' is an anagram of 'tilbu'.
'tilbu'+'ry'='TILBURY'
Can you help me to learn more?
(Other definitions for tilbury that I've seen before include "Thames container port" , "Carriage; Thames port" .)