Analysis On Longitudinal Dynamic Performance Of 10,000T Heavy-Haul Train In Tuoketuo Power Plant Railwayline

Capacity of a heavy-haul train can be improved by enlarging the train formation plans without changing the axle-loads of the locomotive and the vehicle, which could bring significant economic benefits. However, the longitudinal impulse performance will be aggravated with the expansion of train formation plans, which is likely to cause direct or fatigue damage of the carbody and coupler system, or even more serious accidents, such as coupler broken or separation. These effects are bringing threatens to the running safety of the heavy-haul trains. In addition, the coverage area of the train becomes more complex after the expansion, thus the train manipulation will be even more difficult. Simultaneously, increase of the traction tonnage with the expansion will result in high requirement for traction and brake performance. Aiming at Tuoketuo power plant railwayline, a model of 10,000t heavy-haul train is established based on the theory of train longitudinal dynamics. Longitudinal dynamic performances are analyzed in different vertical sections with several control methods. The analyzed results enable supplying theoretical reference for the safety operation after train expansion.According to the operation plans of Tuoketuo power plant railwayline, a longitudinal dynamics model of 10,000t heavy-haul train hauled by double SS4B locomotives is established. By using the model, the longitudinal dynamic performances of the 10,000t heavy-haul train are analyzed in different working conditions. And comparison analysis has been made between the simulation results and experimental results. The analysis shows that the simulation results of train speed and train displacement agree well with the experimental results. As to the longitudinal dynamic indexes, such as train maximum coupler force and train maximum acceleration, there are some differences between simulation results and experimental results. This is mainly caused by discrepancies in initial conditions of vehicles and railwayline condition.The longitudinal dynamic performances of 10,000t heavy-haul train are analyzed in starting and braking mode with different slope angles. The results indicate that, the larger the uphill slope angles are, the worse the starting acceleration performance will be. The slope angle has little impact on train maximum coupler force and train maximum acceleration in the process of starting. Train braking time and braking distance will increase with the growth of downhill slope angles. With the increase of downhill slope angles, the maximum coupler force will be decreased. Meanwhile, the influence of downhill slope angles on train maximum acceleration can be ignored.For the problem of train rushing across slope after marshalling plan expansion in Tuoketuo power plant railway line, the minimum speed method for heavy-haul train rushing across slope is proposed on the principle that the train speed at the top of the slope should not be less than the calculation speed of the locomotives. The train passing through a long downhill section with dynamic braking or electrically and pneumatically blended braking is simulated, respectively. The simulation results show that, the rise-time of dynamic braking force and the initial location at braking application have little influence on the longitudinal dynamic performances of the train. The train speed cannot be controlled effectively only by using dynamic braking. To prevent over-speed accident, electrically and pneumatically blended braking is suggested to be employed when the train passing through the long downhill section. The optimized value of train pipe pressure reduction is 50kPa at the first time and 60kPa at the second time.