What kind of rail needs polishing?
After the opening and operation of rail traffic, rail is long-term in the bad environment, because the train dynamic effect, the natural environment and the quality of rail rail itself and other reasons, often happen damage, such as cracks, wear and other phenomena, resulting in reduced maintenance work, rail service life, increased maintenance costs increase, or even seriously affected traffic safety.
Therefore, the rail damage must be eliminated or repaired in time so as to avoid the safety of rail transit operation. These repair measures, such as rail oiling, rail grinding, etc., in which rail grinding due to its high efficiency by the world wide range of railway applications.
Since the main rail surface defects have been eliminated by corrective or transition sanding, then preventive sanding can be carried out. The purpose of this grinding strategy is to eliminate or control the rail surface defects and ensure the rail surface state and good shape. Usually a small amount of metal (0.2~0.3mm) is removed and the grinding time is more frequent or controllable.Preventive grinding is very economical, especially if only a small amount of metal is removed, the use of grinding tools is reduced, and the service life of the rail is maximized.
The grinding strategy is a long-term rail use strategy (3~6), with the aim of converting the corrective grinding system into a preventive or periodic grinding system. This strategy requires several cycles of grinding, especially when the rails are not very standardized. However, from the cost effect of preventive grinding or periodic grinding strategy, transitional grinding is a better choice, which can ensure the reasonable utilization of limited resources.
Corrective sanding (defect grinding) (Figure 2)The main purpose of this strategy is to eliminate or reduce grinding defects on line rail, generally use the active grinding process, pre designed grinding amount (0.5mm to 4-6mm), and the interval is relatively long, usually by the severity of the defect to decide.Corrective grinding is not very economical, mainly because of the need to remove a large amount of metal on the rail surface, and also requires a large number of grinding processes to reduce the potential service life of the rail. But to ensure that the rail will not fail in a short time, corrective grinding is necessary, especially during the period when the budget for replacing rails is tight. However, this condition of the rail may cause the train speed limit.
