Badly copied rail publication (10)
I believe the answer is:
periodical
'publication' is the definition.
(periodical is a kind of publication)
'badly copied rail' is the wordplay.
'badly' is an anagram indicator.
'copied'+'rail'='copiedrail'
'copiedrail' anagrammed gives 'PERIODICAL'.
(Other definitions for periodical that I've seen before include "Newspaper" , "Publication" , "Magazine" .)