One with a tale to tell is back in this bar (4)
I believe the answer is:
rail
'this bar' is the definition.
(rail is a kind of bar)
'one with a tale to tell is back' is the wordplay.
'one with' is an insertion indicator.
'tale' becomes 'ri' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'to' means one lot of letters go next to another.
'is back' suggests the final letters (the letter at the back).
The last letter of 'tell' is 'l'.
'a' put inside 'ri' is 'rai'.
'rai'+'l'='RAIL'
'in' acts as a link.
Can you help me to learn more?
(Other definitions for rail that I've seen before include "Complain strongly or part of fence" , "transport system" , "Bar; waterbird" , "Length of track" , "Complain about - marsh bird" .)