From the Roanoke Times:
"In a Pullman car built in 1923 but outfitted now with video and laser beams, Norfolk Southern Railway engineering technicians peer at emerging defects in rails.
"Their challenge is to predict when a rail at a certain milepost in the 22-state system will wear thin or get loose enough to cause a derailment.
"The company wants to plan its maintenance so the rail can be fixed just in time to avoid an accident, said Robert Blank, director of research and testing for NS in Roanoke.
“The goal is to make repairs on a schedule that doesn’t interfere with shipping times. That keeps shippers happy, Blank said.”