Traveller who stands, second one getting on holding girl (12)
I believe the answer is:
skateboarder
'traveller who stands' is the definition.
(you stand up on a skateboard)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for skateboarder that I've seen before include "Someone on a short plank with wheels" , "One self-propelled on wheels" , "A berserk toad (anag.)" , "one may roll by" , "sportsman" .)