Old railway porter’s maybe succeeded in freeing chest? (7)

'old' is the definition.
Both the answer and definition are adjectives. Maybe there's an association between them I don't understand?

'railway porter's maybe succeeded in freeing chest?' is the wordplay.
I cannot really understand how this works, but
'railway' could be 'br' and 'br' is present in the answer.
'porter's' could be 'ales' (type of beer) and 'ales' is found within the answer.
'succeeded' could be 's' (genealogical abbreviation) and 's' is located in the answer.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).

Can you help me to learn more?