Track liar shown up over method (7)
I believe the answer is:
railway
'track' is the definition.
(railway is a kind of track)
'liar shown up over method' is the wordplay.
'shown up' says the letters should be written backwards.
'over' says to put letters next to each other.
'method' becomes 'way' (I've seen this before).
'liar' written backwards gives 'rail'.
'rail'+'way'='RAILWAY'
(Other definitions for railway that I've seen before include "Parallel lines" , "Romney, Hythe & Dymchurch, for example" , "Track for trains" , "Transport system" , "Track system" .)