Study On Influence Of Mixed Traffic With Different Speed Grade On High Speed Railway Carrying Capacity

China’s high-speed railway uses transport organization of different speed trains work by collinear and joint operation. This transport organization mode can reduce the transfer of passengers, and meet the travel needs of passengers at different levels, but also reduce the railway carrying capacity due to different speed trains operating collinearly. Based on the above background, this paper mainly studies the influence of factors on the high-speed railway carrying capacity, including different speed trains combination, the proportion of B train, the proportion of B train stops, and drawing method of scheduling passenger train paths. These studies will provide the basis to match different speed trains reasonably in order to ensure good driving condition. The main work in this paper is:(1) Through comparative analysis of transport organization mode in domestic and foreign country were summarized, this paper concluded the reason why "different speed trains work by collinear and joint operation" transport organization mode adapts the development of the high-speed railway in our country at the present stage. This paper summarized the characteristics and influencing factors of high-speed railway carrying capacity in our country, and introduced the methods to calculate high-speed railway carrying capacity and its’applicability, including deduction coefficient method, the average minimum train interval method, and operation diagram compression method.(2) According to the principle of train working diagram compression method, type of train, numbers of train, and stop station scheme in the known as the premise, the compressed schedule calculation model was established, with the objective function that a certain number of trains occupying the shortest time in the train working diagram, and with the constraint conditions including the departure and arrival time area, running time in the section, time interval between two trains, train stop time, the carrying capacity at station, and the drawing method of scheduling passenger train paths. The genetic algorithm to search for the optimal solution was designed. According to occupation times in train working diagram calculated, the high-speed railway carrying capacity in this diagram structure was calculated.(3) Based on the running plan of the upward direction of the Hongqiao Shanghai-South of Nanjing section of the Beijing Shanghai high speed railway, the influence of factors on the high-speed railway carrying capacity were analyzed quantitatively, including different speed trains combination, the proportion of B train, the proportion of B train stops, and drawing method of scheduling passenger train paths. Finally, we summarized the following conclusions:1) The proportion of lower speed trains accounting for 20%,350km/h trains were respectively matched to the 300km/h trains,250km/h trains, and 200km/h trains. The railway carrying capacity decreased by 17% on average when the speed difference per increased by 50km/h.2) Take the 350-250km/h train combination as an example. The railway carrying capacity reduced the fastest by 0.29% when B trains increased 1% in the range of 0% to 30%; The railway carrying capacity was smallest by 102 when B trains accounted for 50%; The railway carrying capacity increased the fastest by 0.26% when B trains increased 1% in the range of 70% to 100%.3) Take the 350-250km/h train combination and B trains accounting for 20% as an example. Under the condition that B train stops unchanged, the railway carrying capacity increased the fastest by 0.33% when the ratio of B train stops for overtaking increased by 1% in the range of 0% to 30%.4) Take the 350-250km/h train combination and B trains accounting for 30% as an example. The railway carrying capacity increased the fastest by 2.84% when B train columns number increased by 1 column in the range of 1 to 4 columns.