Rail Track Definition:
Steel rail track, also called rail track, is an important part of rail. Its function is to withstand the huge pressure of the wheels and guide the train wheels to move forward. The rail should provide a smooth, stable and continuous rolling surface for the passing train wheels. In electrified railways or automatic sections, railway tracks can also be used as rail circuits.
Rail Track Material:
Steel rail track is made of high carbon steel (carbon -0.6% to 0.8%, manganese 0.8%-1.3%, silicon 0.1% -0.5%, sulfur and phosphorus up to 0.03% each, and aluminum up to 0.015%). Certain grades of steel contain chromium (Cr- 0.8% to 1.2%). The rails are also made of special steel containing niobium (max Nb-0.04%) or vanadium (max V-0.2%). Under severe conditions, the rails must be made of corrosion-resistant steel.
The function of Steel rail track in the railway system:
The rail is the most important part of the railway system. It is an inverted T-shaped steel profile. Various rails of different weights and sizes have been developed. All types of rails have hard ends and flat bottoms. This special shape is designed with a set of rail fasteners that fix the rail on the sleeper: rail spikes, screw spikes, elastic rail clips, rail calmps, etc.
Function of Rail Tracks:
1. The rail track provides a continuous and horizontal surface for the movement of the train.
2. The guide rail provides a smooth path with little friction. The friction between the steel wheel and the steel rail is about 3. It is one-fifth of the friction between the pneumatic tire and the metal road surface.
4. The guide rail is used as the lateral rail of the wheel.
5. The rail track bears the stress due to the vertical load transmitted to them through the axles and wheels of the rolling stock and the stress due to the braking force and heat.
6. Through sleepers and ballasts, the steel rails play a role in transmitting loads to a large area of the ground.
Rail Track Components:
The main parts of the rail section are the rail head, web, foot, fishing angle and rail height. The design requirements and main considerations of these rail components are as follows.
1). Head-The head of the steel rail needs to be deep enough to allow vertical wear. The rail head should also be wide enough so that not only can it provide a wider running surface, but the rail also has the required lateral stiffness.
2). Web-The web must be thick enough to withstand the stress due to the load it bears after allowing normal corrosion.
3). Feet-Feet should have enough thickness to be able to withstand vertical and horizontal forces after taking into account the loss caused by corrosion. The feet should be wide enough to prevent overturning. The design of the foot should enable it to roll economically and efficiently.
4). Fishing angle-The fishing angle must ensure that the load is correctly transmitted from the rail to the fish plate. The fishing angle should be such that the tightening of the plate does not cause any excessive stress on the rail web.
Height of Rail Track:
The height of the rail needs to be sufficient so that the rail has sufficient vertical rigidity and strength as a beam.
Steel Rail Requirements:
1. The steel rail should have the most economical section consistent with strength, rigidity and durability.
2. The center of gravity of the rail part should be very close to the middle height of the rail, so that the maximum tensile stress and compressive stress are equal.
3. There should be economical and balanced metal distribution in different parts of the rail so that each part can properly meet its requirements.
Rail Track Length:
The length of the rail track is mainly limited by transportation and thermal expansion. In the rail system, a longer rail means fewer rail connections and less investment in construction and maintenance. Longer rails provide passengers with smooth running and comfortable experience.
Rail Track Structure:
The rail is made of completely killed steel, and each part of the rail should be accurately rolled to its respective template within the allowable tolerance or variation range. All harmful defects, such as various cracks, defects, pipes and lack of metal, should be avoided, which can adversely affect the performance of the rail in use. It must also be absolutely straight. The tolerance of the straightness of the end is very strict.