Length of steel rail
Steel rails are the main components of railway tracks. Its 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 be used as track circuits.
The type of rail is expressed in kilograms per meter of rail mass. The rails used on Chinese railways are 75kg/m, 60kg/m, 50kg/m, 43kg/m and 38kg/m.
The cross-sectional shape of the rail adopts an I-shaped cross-section with the best bending resistance, consisting of three parts: rail head, rail waist and rail bottom. In order to enable the rail to better withstand forces from all sides and ensure the necessary strength conditions, the rail should have sufficient height, its head and bottom should have sufficient area and height, and the waist and bottom should not be too thin.
In my country, the usual length of rails is 12.5 meters and 25 meters. This setting is based on a comprehensive consideration of multiple factors. First of all, considering the efficiency and safety of railway transportation, a moderate rail length can balance the convenience of transportation and the smoothness of train operation. Shorter rails are easy to transport and install, reducing the difficulty of operation; while longer rails effectively reduce the number of joints and improve the smoothness of train travel. In addition, geographical environment and manufacturing standards are also important factors in determining the length of rails.
Internationally, different countries have adopted their own appropriate rail length specifications according to the characteristics of their railway systems. The choice of rail length in my country is a combination of advanced domestic and foreign experience and the actual situation of the country, aiming to achieve efficient, safe and sustainable development of railway transportation. In the future, with the advancement of technology and the growth of railway transportation demand, the length and performance of rails will continue to be optimized to meet the new requirements of railway transportation development.
