List wild tigers by railway (8)
I believe the answer is:
registry
'list' is the definition.
(thesaurus)
'wild tigers by railway' is the wordplay.
'wild' indicates anagramming the letters.
'by' means one lot of letters go next to another.
'railway' becomes 'ry' (abbreviation for railway).
'tigers' is an anagram of 'regist'.
'regist'+'ry'='REGISTRY'
(Other definitions for registry that I've seen before include "Place to keep records" , "Official written record of names, events etc" , "Place of record" , "Place where recorded list is kept" , "Office where records are kept" .)