Oil excited train club (9)
I believe the answer is:
lubricant
'oil' is the definition.
(I've seen this before)
'excited train club' is the wordplay.
'excited' indicates an anagram.
'train'+'club'='trainclub'
'trainclub' is an anagram of 'LUBRICANT'.
(Other definitions for lubricant that I've seen before include "Substance reducing friction" , "Oil or grease" , "Substance used to reduce friction" , "Oil, for example" , "What might have you well oiled" .)