 This was a necessary difference from the predominate concrete arch form of the other bridges of the Overseas Railroad, as the channel is the deepest of those spanned, at 24 feet.The central span is a Parker truss with a span of 247 feet.This is surrounded by 13 Pratt truss sections spanning 186 feet on either side, and 13 smaller Pratt trusses each spanning 128 feet outside those.