Express tribunal unfortunately admitting obstruction (6,5)
I believe the answer is:
bullet train
'express' is the definition.
I don't know anything about this answer so I cannot judge whether it can be defined by this definition.
'tribunal unfortunately admitting obstruction' is the wordplay.
'unfortunately' indicates anagramming the letters (a bad or unfortunate spelling).
'admitting' is an insertion indicator (admit can mean to welcome in or accept).
'obstruction' becomes 'let' (let can mean a hindrance).
'tribunal' is an anagram of 'bultrain'.
'bultrain' going around 'let' is 'BULLET TRAIN'.
Can you help me to learn more?
(Other definitions for bullet train that I've seen before include "Get to work on it fast!" , "Japanese high-speed transport" , "it travels quickly" .)