Rail failure is the damage caused by fracture, crack and other effects and restricting the performance of rail during the use of rail.
In order to facilitate the statistic and analysis of rail damage, the rail damage should be classified. According to the position of the defects on the rail section, the damage appearance and the cause of the defects are divided into nine kinds of 32 kinds of defects, which are classified by two digits number, 10 digits indicate the position and state of the lesion, and the single digit indicates the cause of the defects. The specific contents of rail damage can be seen as "Railway engineering Technical Manual (track)".
The rail break is one of the following: The whole cross-section of the rail is broken into two parts at least, and the crack has been connected with the cross section of the rail head or the bottom section of the rail. Rail breakage directly threatens driving safety and should be replaced in time. Rail crack is the separation of some materials in the rail except the rail break, which forms a crack.
There are many kinds of rail damage, such as abrasion, peeling and axle head, and the crack of axle waist bolt. Several common rail damage cases are described below.