Train in Peru trundling around (7)
I believe the answer is:
nurture
'train' is the definition.
(I've seen this before)
'in peru trundling around' is the wordplay.
'in' indicates the answer is hidden within the clue.
'around' shows that the letters should be reversed in order.
'erutrun' can be found hidden inside 'peru trundling'.
'erutrun' in reverse letter order is 'NURTURE'.
(Other definitions for nurture that I've seen before include "Care for during upbringing" , "Bring up" , "Run true (anag)" , "Care for and protect" , "Supply sustenance to" .)