Dealt with a bit of trouble on the tube (5)
I believe the answer is:
metro
'the tube' is the definition.
('metro' can be a synonym of 'tube')
'dealt with a bit of trouble' is the wordplay.
'dealt' becomes 'met' (meeting is a kind of dealing).
'with' says to put letters next to each other.
'a bit of trouble' becomes 'ro' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'met'+'ro'='METRO'
'on' is the link.
Can you help me to learn more?
(Other definitions for metro that I've seen before include "what moves many Parisians" , "Paris subway" , "Urban railway system" , "French underground" , "The Paris Underground transport system" .)