Whether it's a tiny trestle carrying trains over a small trickle of water or a mighty span wearing a proud name that echoes through railroad history, railroad bridges must be inspected and rein-spected to ensure they can handle increasing loads safely and efficiently. North American Class 1 railroads would have to spend $70 billion to replace existing bridges. Annual spending on bridges by the six largest freight railroads tops $500 million. Many bridges have long since celebrated 100 years of service. New tools and technologies help ensure safety.
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