There are differences between 60kg/m heavy rails and 75kg/m heavy rails in the following aspects:
Dimensions
Height: The height of 60kg/m heavy rails is usually 176mm, and the height of 75kg/m heavy rails is generally 192mm. 75kg/m heavy rails are taller, which can provide larger load-bearing space and stronger bending resistance.
Bottom width: The bottom width of 60kg/m heavy rails is 150mm, and the bottom width of 75kg/m heavy rails is 165mm. The bottom width of 75kg/m heavy rails is wider, and the contact area with the sleepers is larger, which can better disperse the train load.
Head width: The head width of 60kg/m heavy rails is 73mm, and the head width of 75kg/m heavy rails is 75mm. The head of 75kg/m heavy rails is slightly wider, which can increase the contact area between wheels and rails and improve wear resistance.
Weight and theoretical weight
Weight per meter: It can be directly seen from the model that the theoretical weight per meter of 60kg/m heavy rail is 60kg, and the theoretical weight per meter of 75kg/m heavy rail is 75kg. 75kg/m heavy rail is heavier, with greater mass at the same length, and can better maintain the stability of the track.
Mechanical properties
Strength: Due to its larger size and heavier weight, the overall strength of 75kg/m heavy rail is higher than that of 60kg/m heavy rail, and it can withstand greater train axle weight and impact force. For example, when subjected to the same load, the deformation of 75kg/m heavy rail is relatively small.
Toughness: Both need to have good toughness, but 75kg/m heavy rail may have certain advantages in toughness due to the larger material usage, and can better adapt to the complex railway operation environment and reduce the risk of brittle fracture.
Wear resistance: The rail head of 75kg/m heavy rail is wider, the contact area between the wheel and the rail is large, and the pressure per unit area is relatively small, so it performs better in wear resistance, which can extend the service life of the rail and reduce the frequency of maintenance and replacement.
Application scenario
60kg/m heavy rail: Commonly used in national railway trunk lines, busy freight lines and some high-speed railways, it can meet the requirements of most ordinary railway transportation and is a widely used heavy rail specification.
75kg/m heavy rail: Mainly used in extra-heavy railway lines, such as large-scale mining railways, heavy-duty freight lines and special places with extremely high requirements for rail bearing capacity, and can withstand overweight train loads.
Manufacturing cost
Raw materials: 75kg/m heavy rail consumes more raw materials such as steel per meter, which directly leads to its raw material cost being higher than 60kg/m heavy rail.
Production process: Due to the large size and weight of 75kg/m heavy rails, the production process has higher requirements for rolling equipment, heating process, cooling control, etc., and the production difficulty is relatively large, which will also increase its manufacturing cost. Therefore, the price of 75kg/m heavy rails is usually higher than that of 60kg/m heavy rails.