FREIGHT RAILROAD BRIDGE SAFETY KEY FACTS

• Trained experts under federal rules inspect more than 61,000 railroad bridges at least annually.
• Drones, sensors, and engineering programs catch issues early.
• Rust and appearance don’t dictate safety.

Thousands of bridges are critical to rail’s network. They allow trains to cross rivers, gorges, and ravines. Railroad overpasses also improve traffic flow for pedestrians and vehicles. Without strong bridges, America’s freight rail system could not function. That’s why railroads invest billions each year. They employ highly trained bridge safety experts and inspect more than 61,000 Class I bridges annually.

Regular inspections are essential for safe train operations. Federal regulations require trained experts to inspect every railroad bridge at least once a year. Bridges with heavy traffic or special conditions receive more frequent checks. Railroads follow a strict “safety first” policy and suspend service on any bridge until concerns are resolved.

Every railroad has a bridge program.

Federal Railroad Administration (FRA) regulations mandate that railroads maintain comprehensive bridge safety management programs. These programs, accessible to relevant personnel, guide inspection, evaluation, and structural work methods. The FRA, along with state oversight, ensures compliance. They participate in accident investigations, perform assessments, provide technical guidance, and issue penalties or emergency orders if necessary.

Each bridge management program documents details such as safe loads, weights, and speeds for all railroad bridges. It also outlines inspection schedules, repair processes, and additional assessments required after accidents or adverse weather events.

These programs restrict the transportation of loads beyond approved limits. Qualified railroad bridge engineers make exceptions. They also mandate annual inspections of all rail bridges and specify repair processes. Inspectors conduct additional assessments after incidents that may affect structural integrity. Regular internal and FRA audits ensure program effectiveness. They validate inspection reports, inventory data, verify correct movement restrictions, and confirm adherence to program requirements by railroads.

Specialized teams inspect railroad bridges.

Railroads assign a specialized team, including a railroad bridge engineer, inspector, and supervisor, to develop custom inspection procedures tailored to each bridge. These procedures aim to detect and address potential hazards. They focus on mitigating specific threats to bridge safety, such as seismic risks in earthquake-prone areas. The inspection team visually reviews all components, including underwater analysis when necessary. They employ advanced techniques like ‘sounding’ or ‘boring’ for non-visible elements.

Identified anomalies, such as cracks, loose connections, or structural distortions, prompt further analysis. Inspection findings are promptly filed with the railroad’s bridge management program. They are reviewed by supervisors and engineers and shared with the FRA for assessment. The railroad allocates funds for and executes necessary maintenance, repairs, or replacement. Bridge supervisors ensure compliance with design specifications for safe train operation.

Railroad bridge safety reports determine if a structure is fit for its intended use.

Qualified professional engineers develop railroad bridge safety reports. They evaluate whether each structure is fit for its intended use. Engineers base these evaluations on rigorous standards and conduct them under federal regulations to ensure public safety. They assess private property maintained through private investments—not publicly funded infrastructure used by motorists like those in the FHWA data set.

Currently, access to these reports is available to state and local agencies, such as departments of transportation, through a formal request process administered by the FRA. The FRA grants access when it deems a request reasonable. AAR supports this existing framework, which appropriately balances public transparency with infrastructure security.

While well-intentioned, broader public disclosure of these technical details could lead to unintended consequences. Misinterpretation of engineering assessments by non-experts could create unnecessary alarm. More critically, access to these detailed structural information may pose safety and security risks to critical infrastructure. 

Technology makes bridges safer.

Railroads are increasingly incorporating drones for bridge inspections, with a focus on advancing predictive maintenance strategies. Exploration of alternative bridge designs and materials, including retrofits and innovative constructions, is underway to enhance structural resilience. The integration of science-based inspection methods, robotic-assisted tools, machine vision, and onboard detection capabilities aims to deliver more accurate information. This information aids in informed capital and maintenance decisions.

Looking ahead, selected bridges may feature in-track, self-diagnosing condition monitoring systems. These will foresee potential failures well in advance. Leveraging wireless communication systems, smart sensor networks can provide actionable insights into the structural integrity of bridges. This further optimizes maintenance efforts for railroads.

From the Expert: Cosmetic imperfections on railroad bridges don’t necessarily indicate safety issues.

Scientist Dr. Duane Otter, a Principal Engineer at MxV Rail who recently advanced to the grade of Fellow in the Structural Engineering Institute (SEI) of the American Society of Civil Engineers (ASCE), knows a thing or two about railroad bridges.

“We have steel bridge spans at our test facility that are over 100 years old,” says Dr. Duane Otter, principal engineer at MxV Rail. “They may be old, but we’re finding that many old bridges like these are safe and strong — well beyond the lifespan that was envisioned when they were first built.”

Dr. Otter credits railroad bridge health and longevity to generations of railroad bridge engineers. They took a conservative design approach to build bridges that could carry the immense weight of steam-powered locomotives. Some of these original iron horses placed tremendous stress on rail bridges in the early 20th century. Today’s environmentally friendly modern locomotives place less stress on railroad bridges.

In the years since the early 1900s, railroads have closely monitored locomotive and car weights. The industry’s conservative approach to bridge construction — and maintenance and inspection — has been instrumental. This approach has allowed those bridges to remain in continued safe service.

As the years have progressed, the traditional manual inspection process has improved with “snooper trucks” — specialty trucks fitted with a retractable arm and bucket for inspectors. The introduction of this method, still the primary approach today, sped up the process and improved inspection safety. However, it requires temporarily pausing train traffic on a portion of track in order to inspect the bridge.

“Railroads have well-tested guidelines for determining the frequency of inspections. These are based on the weight of trains, volume of train traffic, and the types of traffic going over bridges — such as passengers or hazardous materials,” says Dr. Otter. “Railroads will often increase the frequency of inspections if a bridge shows initial signs of wear or tear that are significant from a safety standpoint.”

Although some bridges may look outdated to the general public, appearances are deceptive. The simple design of most railroad bridges makes them simple and efficient to repair. This contributes to a safe, extended life. Just because a bridge has rust does not mean that it’s dangerous. In fact, additional aesthetic design elements, such as decorative beams or arches, can inhibit access for inspection of a bridge. For the railroads, form follows function.