Humpback bridges Not railroad bridges, but rather auto bridges over railroads, humpback spans were built in an era when auto and truck traffic volumes were much lower than today. Shown here are two examples, a wood-and-steel span at Lula (above) and a concrete-and-steel bridge at Toccoa. Both cross over Norfolk Southern's Atlanta-to-Charlotte line. Georgia's Railroad History & Heritage. Copyright, Steve Storey. Railroad History | The Depot List | Locomotives On Display | Odds & Ends | Sources & References | Home