Happy to find this writer right by railway (5)
I believe the answer is:
merry
'happy' is the definition.
(thesaurus)
'this writer right by railway' is the wordplay.
'this writer' becomes 'me' (the person who is writing these clues).
'right' becomes 'r' (common abbreviation).
'by' is a charade indicator (letters next to each other).
'railway' becomes 'ry' (abbreviation for railway).
'me'+'r'+'ry'='MERRY'
'to find' is the link.
(Other definitions for merry that I've seen before include "Jolly and gay" , "Joyous, cheerful" , "Cheerful, lively" , "Mistresses Page and Ford of Windsor" , "Jovial" .)