What is a track?

In rail transportation, steel rails are an important component that can ensure the smooth running of trains. Since its invention in 1767, the steel rail has undergone more than 250 years of development and evolution, and its excellent physical properties are closely related to its shape, material, and production process. With the continuous advancement of railway technology, the section of the rail has also undergone a process from flat to T-shaped to U-shaped, and it was not fixed to I-shaped until 1864.

The rail is composed of rail head, rail waist and rail bottom. After the top surface of the I-shaped rail reaches a certain specification in width and thickness, it can maintain a stable and strong state; in order to take into account the stability of the rail, the width of the bottom surface of the rail is also To achieve a certain specification and increase the force bearing area; in addition, the wheel must be in line with the rail in structure, and the wheel has a rim, so the height of the rail needs to be high enough to accommodate the lower rim. Therefore, the I-shaped section is recognized as a good rail section structure in the industry, especially from the point of view of material mechanics, the I-shaped rail has a good performance in strength, and it has been used until now because it can show the utilization rate of steel.

The main component of the rail is iron, in addition to carbon, manganese, silicon, sulfur and other elements. Among them, carbon is an element with a large content other than iron, which determines the strength, hardness and wear resistance of the rail, but the content of carbon should not be too much, otherwise it will increase the brittleness of the material and cause other shortcomings. Manganese determines the strength and toughness of the rail and also reduces the side effects of sulfur. Silicon element can eliminate oxygen and bubbles in molten steel, thereby increasing the density of steel. However, both phosphorus and sulfur elements have adverse effects on the rail. The former will make the rail cold brittle, and the latter will make the rail hot brittle. Both elements should be removed as much as possible.

Usually the length of the rails on the track is 12.5 meters or 50 meters, but not all the rails are seamless. There will be gaps in the lines connected by splints and connecting parts in the middle, which are called joint rail gaps. The joint rail seam is to avoid the mutual extrusion of the rails due to thermal expansion and expansion, which will cause the rails to be twisted and arched, making the rolling stock unable to run normally. In addition, we heard the sound of "banging, banging, banging" when we were riding the train, which was produced when the train wheels pressed through the rail gaps.

Compared with other means of transportation, rail transportation has obvious advantages. It not only has a large loading capacity, but also has a long transportation distance, low transportation cost, and little impact on climate. Now it has become a major transportation method.