Which type of bridge railing is constructed primarily using steel materials?

• A. Tubular rail system
• B. Steel bridge railing
• C. Box beam guardrails
• D. Cable railings

Answer: (B)

The key idea here is that the defining feature of this railing type is its dominant material. A steel bridge railing is built mostly from steel members—posts, rails, braces, and connections—fabricated as a cohesive steel system. This provides the strength, stiffness, and durability needed for bridge environments, so it’s clearly described by its primary material as steel.

Tubular rail systems can use steel tubes but aren’t defined solely by that material and may vary; box beam guardrails can be steel or other materials depending on design; cable railings rely on steel cables and fittings, but the railing surface isn’t a solid steel rail in the same sense. So the option that explicitly centers steel as the primary material best matches the question.