There are a few different classes of wheel flat (skidded wheel) which are caused by the wheel sliding along the rail allowing the tread metal to be removed to create a flat section. It is important that a skidded wheel is identified quickly as it can lead to high impact forces, a cracked wheel, cracked rail, broken rail and possible train derailment. It is more cost-effective to change the wheelset out to re-machine and return it to service, than clean up a derailment which can cost millions. Aurizon's Condition Monitoring teams are using Trackside Interface Equipment (TIE) to detect surface defects such as cracked/broken wheels in Queensland coal fleet. In some condition analyses for all locomotives in Aurizon's Queensland Coal fleet, the results showed that the most common fault on locomotive wheel treads was skidded wheel termed as Defect Code 02 and sometimes it is indicated. This consequently sparked a detailed investigation into assessing the condition monitoring methods for preventing catastrophic failure and derailments.