Where the Welsh don't allow rail transport? (5)
I believe the answer is:
barry
'where the welsh don't allow' is the definition.
The definition suggests a singular noun but the answer is not.
'rail transport?' is the wordplay.
'rail' becomes 'bar' (I've seen this in other clues).
'transport?' becomes 'ry' (abbreviation for railway).
'bar'+'ry'='BARRY'
Can you help me to learn more?
(Other definitions for barry that I've seen before include "-- Island, Welsh resort" , "South Wales town -- boy's name" .)