Tram travelled with gold cannon (6)
I believe the answer is:
mortar
'cannon' is the definition.
(I know that mortar is a type of high-angle gun)
'tram travelled with gold' is the wordplay.
'travelled' indicates anagramming the letters.
'with' is an insertion indicator.
'gold' becomes 'or' ('or' is the heraldic name for gold).
'tram' is an anagram of 'mtar'.
'mtar' going around 'or' is 'MORTAR'.
(Other definitions for mortar that I've seen before include "Building adhesive" , "Bonding material for bricks" , "Small cannon or building material" , "Brick cement" , "Lime mixture; a cannon" .)