Confused communist next to railway district (5)
I believe the answer is:
derry
'confused communist' is the definition.
The definition suggests a singular noun which matches the answer.
'next to railway district' is the wordplay.
'next to' says to put letters next to each other.
'railway' becomes 'ry' (abbreviation for railway).
'district' becomes 'der' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'ry' put after 'der' is 'DERRY'.
Can you help me to learn more?
(Other definitions for derry that I've seen before include "Port" , "Ulster city" , "'The London - - Air' (mus.)" .)