Who is Wagga McBride from Cloudstreet and what is their importance?

Wagga McBride is one of Quick's classmates. He and his brother always bend over their food, something Quick realizes is their way of disguising the fact they are only pretending to eat.... the boys actually have no food. Quick gives them food, and he even follows them home one day. Unfortunately, in following them home, Quick witnesses Wagga as he is hit and killed by a train while he and his brother play beside the railroad tracks.