Classification of rails

Rails are the main components of railway tracks. Their function is to guide the wheels of locomotives and vehicles forward, bear the huge pressure of the wheels, and transmit it to the sleepers. Rails must provide a continuous, smooth and least resistant rolling surface for the wheels. In electrified railways or automatic block sections, rails can also serve as track circuits.

At present, the rails that have been finalized and produced in my country are mainly divided into the following three categories:

Classification by steel type: including carbon rails and alloy rails. Carbon rails effectively improve strength and optimize toughness through the reasonable combination of carbon (C) and manganese (Mn) elements, such as U71Mn, AP1 and U74. Alloy rails, on the basis of carbon rails, incorporate alloy elements such as vanadium (V), titanium (Ti), chromium (Cr) and molybdenum (Mo) to further enhance the strength and toughness of rails, such as PD1, PD3 and V-Ti rails.

1.Classification by weight: my country's rails have various weight specifications, including 38 kg/m (P38), 43 kg/m (P43), 45 kg/m (P45), 50 kg/m (P50), 60 kg/m (P60) and 75 kg/m (P75).

2.Classification by mechanical properties: divided into ordinary rails, high-strength rails and wear-resistant rails. Among them, the tensile strength of ordinary rails is not less than 800 MPa; the tensile strength of high-strength rails reaches 900 MPa or above; and the tensile strength of wear-resistant rails is as high as 1100 MPa or above.

The cross-section of a rail is a symmetrical I-shaped rail, which consists of three parts from top to bottom: the rail head, the rail waist and the rail bottom. The cross-sectional dimensions and screw hole positions of different types of rails are different.
8, 43, 45, 50, 60 and 75, these numbers represent the weight specifications of my country's rails, which are closely related to the strength and applicable occasions of the rails.