UC San Diego Creates Real-Time Rail Safety Imaging Device

A new device no bigger than a train wheel could prevent hundreds of railroad accidents across America by spotting invisible cracks before they cause catastrophic failures.

Engineers at the University of California San Diego have spent two decades perfecting an ultrasound system that does something current rail inspection tools cannot. It creates real-time, high-resolution images of defects hidden inside railroad tracks as inspectors push a cart along the rails at walking speed.

The technology matters because America's vast 140,000-mile rail network is aging, and internal cracks that are invisible to the naked eye cause hundreds of service failures every year. When these hidden fractures break under a train's weight, the results can be devastating.

Current inspection methods require a two-step process that's both slow and limited. Automated vehicles crawl along tracks at 25 miles per hour, flagging potential problem areas. Then inspectors manually check each flagged spot using handheld devices that show only waveform data, not actual images of what's happening inside the rail.

Professor Francesco Lanza di Scalea and his team changed that by combining two different types of ultrasound technology with new algorithms. The result is a device that shows inspectors exactly what internal defects look like, where they're located, and how serious they are.

Postdoctoral scholar Chengyang Huang solved a critical engineering challenge: how to maintain clear images while the device moves quickly over tracks. "It's always an engineering tradeoff. If you go faster, you lose signal," Huang explained. The team cracked the code by merging phased array and synthetic aperture ultrasound methods.

The researchers successfully demonstrated their device at MxV Rail's Colorado research facility in August 2025. They're now working with MxV Rail to determine the most practical setup for widespread field use and conducting extensive validation tests.

The Ripple Effect

This innovation arrives at a crucial moment as America expands its high-speed passenger rail network. The device could eventually be embedded directly into train wheels, creating truly smart trains that inspect every mile of track they travel without slowing down.

The same ultrasound technology that lets expectant parents see their babies is now protecting the millions of people who depend on safe rail transportation every day. Lanza di Scalea's lab has been a leader in railroad safety research for years, conducting materials tests for California's High Speed Rail authority and serving on key national rail engineering committees.

What started as a university research project is becoming a practical tool that could save lives and prevent costly disruptions across America's critical rail infrastructure.