Toboggan initially stored on shelf (6)
I believe the answer is:
sledge
'toboggan' is the definition.
(I've seen this before)
'initially stored on shelf' is the wordplay.
'initially' says to take the initial letters.
'on' is a charade indicator (letters next to each other).
'shelf' becomes 'ledge' ('ledge' can be a synonym of 'shelf').
The first letter of 'stored' is 's'.
's'+'ledge'='SLEDGE'
(Other definitions for sledge that I've seen before include "Vehicle mounted on runners" , "Transport on snow - hammer" , "Vehicle for use in snow" , "Vehicle for travelling over snow" , "In the field, abuse" .)