The components that wear fastest in the railway system are the
wheels. The rails persist longer, but not forever, they wear also.
Excessive wear with other defects affect not only the riding
quality but also safety of the rail vehicles. This sets on its
part great requirements regarding the control of wear and the
effectiveness of the maintenance system.
In view of the huge costs the wheel and rail maintenance involve, a well planned maintenance program is an essential factor in pursuit of minimizing costs and maximizing savings in material. Besides thoroughly planned, the control system should be a continuous and well supervised process, largely accepted by the persons concerned. It should produce information that is felt important on all levels of the organization.
In addition to several measures available to improve wheel life, such as lubrication, adapted wheel profiles, developed wheel metallurgies, etc., the need to reprofile or replace wheels and rails forms a considerable cost item for railway operators. The loss of material together with the involved labor costs and non-productivity periods, when vehicles are not in service, are elements that are to be considered in the planning and scheduling of a comprehensive wear control system.
The most essential part of such a system is the availability of accurate measuring data produced by reliable measuring instruments. These instruments should be precise enough to meet the established requirements in each particular case. These devices shall also be handy and easy to use, ready to operate without special demands for installing or mounting. A risk for an inaccurate or false result should be minimized.
The efficiency of modern wear control implies that the measuring results are produced in numerical data available for processing by computers.