According to statistics, there are about 10,000 kinds of rubber materials and components used in railways and locomotives, and about 10 kt/ an of rubber is consumed. With the increase of the speed of railway locomotives, the dynamic effect on the lines has increased dramatically, causing severe wear on the components of lines, tires, and parts of the locomotives. The requirements for seismic resistance of railway locomotives have become higher and higher, and rubber shock absorbers have become increasingly demanding. Applications are becoming more and more popular, and thus more and more varieties and quantities of shock-absorbing rubber products are being used on locomotives. The rubber damping products on railway locomotives mainly include central supporting rubber stacks, axle box rubber springs, side bearing rubber stacks, motor suspension rubber pads, elastic wheels, elastic gears, rubber air springs, and bow rubber blocks of transmissions. Rubber ball hinge, coupler rubber buffer and so on. The rubber shock absorbers used in locomotives are mainly used to withstand compressive stress, shear stress and torsional moment as well as to withstand 2 or more kinds of stress composite action at the same time.
With the rapid development of railway construction, the railway sleepers are gradually changed from sleepers to concrete sleepers. After the replacement, although the service life of the sleeper is prolonged, the stability of the track frame structure is improved, but the elasticity of the track is significantly reduced, resulting in deterioration of the cushioning of the track to the wheel-rail impact. In order to improve the cushioning performance of concrete sleepers, reduce the impact of sleepers on track beds, and increase insulation, elastic polymers are used at home and abroad to solve the problem of the elasticity of concrete sleeper tracks. Rubber sleeper pads are elastic pads used between rails and concrete sleepers or under pillows (in addition to soft soil and rubber sleeper pads, laminated wood rails, and plastic sleeper pads, etc.). Rubber sleeper pads are unique in their elasticity and good insulation. Performance is widely used on railway lines.
According to different uses, concrete sleeper rubber pads are generally divided into two types: pillows (below the rails) and pillows. Due to long-term exposure to the atmosphere and under the pillow, rubber sleepers are constantly subjected to vibrations and impacts when passing through the locomotive. Therefore, they are required to have good resistance to natural aging, heat resistance, cold resistance, good elasticity, cushioning, and shock absorbing properties. Also have good wear resistance, electrical insulation, compression, and shear resistance. The most important thing in formulation design is to consider the durability of materials and the low cost. Commonly used main materials are NR, SBR, BR, CR, EPDM and so on.