Background

Railroad rails are held in place by a series of spikes driven into the ground and securing the rail. These spikes experience substantial stress whenever the railroad is used. Over time, these stresses crack and break the spikes, severely degrading the safety of the railroad. Several recent derailments in Canada and the United States were caused by a number of broken spikes or screws within a certain section of a track.

Thus, frequent testing of these spikes is crucial to railroad safety. Current maintenance approaches need specialized sensors or extraction equipment to simply pull up the spike and check if the spike is broken. These approaches are expensive, not portable, and hard to operate. Thus, there is substantial need for a method of nondestructively testing railroad spikes that is cheap, portable, and simple to operate.

Technology Overview

NC State researchers have developed a novel method of non-destructively identifying broken and partially cracked railroad spikes that is cheap, highly portable, and easy to operate. The test is conducted by striking the head of the railroad spike with a specialized device, which causes a certain vibration and sound. Utilizing highly specialized and custom software analysis tools developed by NCSU, the researchers capture these vibrations and sound to nondestructively test the railroad spikes. The sound analysis software accounts for all relevant environmental variables, such as rust, weather, and railroad tie placement, etc. This allows for a very high degree of accuracy in testing.

Thus, by capturing the sound with a microphone and inputting the recording into a custom developed sound analysis software, the NCSU researchers have shown the ability to nondestructively test the railroad spikes. The sound analysis software accounts for all relevant environmental variables, such as rust, weather, and railroad tie placement, etc. This allows for a very high degree of accuracy in testing.

This software has been tailored to railroad spike analysis, but the principle could possibly be applied to wide variety of nondestructive testing applications.

Benefits

Nondestructive testing of railroad spikes.
Low effort, low training, low cost, easily portable testing system.
Will help prevent train derailments, thus saving lives.
Potential nondestructive testing of other metal objects and tools.

Applications

Railroad maintenance
Non-destructive testing of various metal objects, including by not limited to, railroad spikes

Low-Effort, Nondestructive Testing of Railroad Spikes