New Scientist is reporting that the FDA is testing some new hardware that locates flaws in rail lines using lasers.
The laser pulses create ultrasonic waves that travel through rails at high speed. This means the device can scan for cracks while being pulled along a rail track at up to 112 kilometres (70 miles) per hour – much faster than existing equipment. The machine identifies microscopic fractures by monitoring the strength of ultrasonic waves passing through a rail.
The lasers vaporise a very small amount of the top of the track as they simultaneously generate transsonic waves that can be detected by a microphone positioned ahead of and above the track. This is much improved over previous methods which limited the testing speed to 50 km/hr.