Strip used to decorate train baby owns occasionally (6)
I believe the answer is:
ribbon
'strip' is the definition.
(I know that ribbon is a type of strip)
'train baby owns occasionally' is the wordplay.
'occasionally' indicates alternate letters (letters taken at regular intervals or occasions).
'train'+'baby'+'owns'='trainbabyowns'
The alternate letters of 'trainbabyowns' are 'RIBBON'.
'used to decorate' acts as a link.
I am not very happy about this link. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for ribbon that I've seen before include "Fabric woven in strip" , "Strip of ornamental cloth as for hair" , "Thin strip of cloth" , "Long, narrow band" , "Narrow strip of coloured cloth, worn as ornament" .)