Shifty liar with a system at chemin-de-fer (7)
I believe the answer is:
railway
'chemin-de-fer' is the definition.
I can't tell whether this defines the answer.
'shifty liar with a system' is the wordplay.
'shifty' is an anagram indicator.
'with' says to put letters next to each other.
'a system' becomes 'way' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'liar' is an anagram of 'rail'.
'rail'+'way'='RAILWAY'
'at' is the link.
Can you help me to learn more?
(Other definitions for railway that I've seen before include "Parallel lines" , "Track system" , "eg Funicular" , "Means of transport" , "Train system" .)