关键词: 装车地, 铁路区段, 牵引定数, 端点换重, 直达列车

Abstract: Railway transportation is the main transport mode for bulk cargo transport. The flow of wagon generated in the railway network should be primarily consolidated into that of the direct cargo train in the original loading area and then delivered to that of their destination stations. For those wagons not consolidated into the direct cargo train in the original loading area, they will be delivered to adjacent technical stations and collected to organize the other type of train, i.e. the direct cargo train from technical stations. Therefore, this will reduce the reclassification work from the intermediate station, relieve the workload of technical stations and make the organization of cargo trains more efficient, so that the wagons are prioritized in the original loading area and the cargo train operation scheme is optimized.
China’s railroad network is composed of many rail block sections with various train-carrying capacities. That is to say, the train traction tonnage allowed corresponding to different rail block sections is not the same. The characteristic of the unbalanced block section carrying capacity is caused by the railroad line level, topographic condition and marshalling infrastructure. Due to the disturbance caused by the inconsistent train traction tonnage and unbalanced carrying capacity of block sections located at the train journey, two types of train operation modes are usually adopted, i.e. the constant train traction tonnage scheme and train load transfer scheme. But no matter which scheme is adopted, this will bring some negative impacts. Specifically, the constant train traction tonnage scheme may lead to trains coupling insufficient wagons and running below rated traction tonnage along some rail sections. Moreover, the train load transfer scheme is likely to cause the additional train detention time generated at the intermediate switch station. Therefore, it is an urgent problem to be solved how to scientifically work out the train operation scheme to improve the utilization of railway network with unbalanced block section carrying capacity.
Aiming for railway network with unbalanced block section carrying capacity, a multi-mode hybrid operation scheme of the train from the loading area is studied. It can minimize the impact caused by the inconsistent train traction tonnage and unbalanced block section carrying capacity. Firstly, a train formation plan based on the constant traction tonnage according to the minimum carrying capacity of block sections along the train running corridor is studied. Three combination operation modes of trains from the loading area are given. And the objective function intends to minimize wagon-hour consumption induced by loading/unloading work at the handling station, reclassifying the train at the middle technical station and the light load train wasting block section carrying capacity. Then some constraints indicating per centralized loading capacity limitation and unique wagon flow arrangement are considered. So, a train combination operation model based on constant traction tonnage is developed. Secondly, a train formation plan based on dynamic traction tonnage caused by pick-up and cut-off work at the intermediate switch station is studied. Two combination operation modes of trains from the loading area are introduced. So, a train combination operation model based on train load transfer is presented. Finally, the two types of proposed train combination operation schemes are merged to set up a hybrid train operation scheme integrating the constant traction tonnage and dynamic traction tonnage.
A case study according to the Binzhou railway corridor of the Hailar loading station is given to test the train constant traction tonnage scheme and train load transfer scheme. The study goes a step further to achieve a hybrid train operation scheme by integrating the two above-mentioned schemes. The testing results show that the wagon-hour consumption induced by the constant train traction tonnage scheme and train load transfer scheme are 18817.24 and 12743.33, respectively. Obviously, the train load transfer scheme is more advantageous. And the further testing indicates that the hybrid train operation scheme can reduce the wagon-hour consumption to 12107.44.
The current study focuses on the railroad network with the physical path of only one wagon flow between pairs of handling stations. The next research work will aim at the complex railroad network with many wagon flow physical paths between pairs of handling stations.

Key words: loading area, block section, tonnage of traction, train load transfer, direct train