Crane wheels gnaw at the rails—crucial impact of crane trolley wheels

During operation, the crane's trolley wheels may experience lateral sliding against the rail due to certain factors, causing the wheel flanges to tightly press against the rail and significantly increasing running resistance. This phenomenon, where wheel flanges wear down the rails, is known as "rail biting." Rail biting drastically shortens the service life of both wheels and rails—and in severe cases, it can even lead to the crane derailing, resulting in equipment damage, injuries, or even fatalities. Additionally, rail biting can cause varying degrees of harm to the rail fastenings as well as to the supporting structures, such as building beams (or track foundations).

1. Rail biting caused by inaccurate wheel installation

(1) Excessive horizontal deviation of the wheels is a common cause of wheel flange wear on the rails of bridge cranes. When the horizontal deviation exceeds the specified limit, the centerlines of the wheel rolling surfaces form an angle with the centerline of the rail. As a result, while the crane moves in one direction, the wheel flange scrapes against one side of the rail; but when the crane reverses, the same wheel flange begins to scrape against the opposite side—creating an inconsistent and unpredictable pattern of rail wear. According to installation guidelines, the horizontal deviation must not exceed L/1000 (where L is the measured length on the wheel), and the skew directions of a pair of wheels mounted on the same axle must be opposite. Otherwise, wheel flange wear on the rails is almost inevitable.

(2) Excessive vertical deviation of the wheels—specifically, when the centerline of the wheel flange forms an angle with the plumb line, causing the wheel to tilt. In this scenario, the contact area between the rolling surface of the wheel and the rail tread decreases, while the pressure per unit area increases significantly. As a result, wear on the wheel’s rolling surface becomes uneven, and in severe cases, circular wear grooves may even develop. A key characteristic of wheel flange wear under these conditions is that the wheel flange consistently gnaws on the same side of the rail—the tilted side—while the resulting rail marks tend to be slightly deeper than usual. Additionally, cranes often emit a hissing sound during operation. When installing wheels, it’s crucial to ensure that the vertical deviation does not exceed L/400, and the upper part of the wheel should be positioned outward. It’s important to note that wheel-related rail啃轨 caused by vertical deviation refers specifically to the driving wheels and is unrelated to the driven wheels.

(3) Unequal wheel gauge and diagonal distances, as well as poor straightness of the two wheels on the same track, can also cause crane wheels to climb or "bite" the rails. In these cases, the characteristic wear pattern is observed on both sides of the rail where the wheel flanges come into contact.

2. Rail biting caused by wheel machining errors: During the manufacturing process, inaccuracies in wheel machining result in uneven wheel diameters. If the two driving wheels have mismatched diameters, their running speeds will differ when in operation. Over time, this discrepancy causes the vehicle body to veer off course and shift laterally, ultimately leading to rail biting—a phenomenon that is especially pronounced in centrally driven systems.