钢轨端部轨头下颚处水平裂纹(附图),通常被认为是钢轨断面设计不良,轨头下颚及轨腰与轨底连接处的圆弧半径太小,在荷载作用下局部应力过大而产生的。线路养护不当也会促使此种裂纹产生。早期设计的钢轨,上述圆弧半径都较小,此种伤损也较多。后来设计 The horizontal cracks at the jaws of rail head railhead (with photos) are usually considered as bad rail cross-section design. The radius of the circular arc at the junction between rail jaw and rail waist and rail bottom is too small, and the local stress is too large under load produced. Improper maintenance of the lines can also encourage such cracks. Early design of the rail, the arc radius is smaller, such injuries are more. Later design