Tram crashed and, top open, pushed in spontaneously (2,6)
I believe the answer is:
at random
'pushed in spontaneously' is the definition.
I can't judge whether this definition defines the answer.
'tram crashed and top open' is the wordplay.
'crashed' indicates an anagram.
'top' becomes 'o' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'open' is an insertion indicator (some letters open a gap in others).
'and'+'o'='ando'
'tram' with letters rearranged gives 'atrm'.
'atrm' enclosing 'ando' is 'AT RANDOM'.
Can you help me to learn more?
(Other definitions for at random that I've seen before include "Indiscriminately" , "Haphazard" , "Haphazardly" , "without purpose" , "Casually" .)