Flat Wheel MPS Run is always Soothing to Ears. Lucky are those who get to travel in that Coach :)
Flat wheel is a condition where the Rail carriage's round wheel shape gets dented. This denting occurs when the non-rotating wheels are dragged along the rails in conditions such as emergency braking, Slipping, and overload.
This phenomenon occurs in Passenger coaches as...
more... well as freight carriers.
When such a phenomenon arises, the wheels are inspected to identify the severity of the dent, if it is a minor cause, the wheels would be run for further service and will be corrected at the time of Periodic or Annual Over Haul.
If the dent is severe then the carriage is straight away sent to the workshop to replace the dented wheel with a new wheel set.