Long walk from public transport beginning to pall (5)
I believe the answer is:
tramp
'long walk' is the definition.
(I've seen this before)
'public transport beginning to pall' is the wordplay.
'public transport' becomes 'tram' (type of public transport).
'beginning to' says to take the initial letters.
The initial letter of 'pall' is 'p'.
'tram'+'p'='TRAMP'
'from' is the link.
(Other definitions for tramp that I've seen before include "Merchant ship" , "I might hitch a lift" , "Disreputable wanderer" , "Ship, possibly" , "cargo-boat" .)