One with runners was at the front after second (4)
I believe the answer is:
sled
'one with runners' is the definition.
(sleds have runners)
'was at the front after second' is the wordplay.
'was at the front' becomes 'led' (e.g. led a march).
'after' says to put letters next to each other.
'second' becomes 's' (common abbreviation).
'led' after 's' is 'SLED'.
(Other definitions for sled that I've seen before include "Sledge" , "Winter transport" , "Toboggan (mainly US)" , "Snow transport" , "Goods vehicle" .)