STUDY ON THE CARRYING CAPACITY OF RAILWAY NETWORK AND TRANSPORT PROGRAM.doc

专业文档，值得收藏！study on the carrying capacity of railway network and transport programzilan wang1, ciguang wang 2 and hui fang 31department of traffic and transportation, southwest jiaotong university, no.1, jingqu road, emeishan sichuan 614202, china; ph(86 email: 2school of traffic and transportation, southwest jiaotong university, no.111, 1st section, north of 2nd ring road, chengdu sichuan 610031, china; ph(86)(028)87603641; email:3school of traffic and transportation, southwest jiaotong university, no.111, 1st section, north of 2nd ring road, chengdu sichuan 610031, china; ph(86 email:abstract: constructing a developed complete railway network and promptly expanding the carrying capacity of railway network are main tasks of railway span development. regarding railway network as a system, the researchers have done little things about the concepts and theories of network capacity because of its complexity. the definition of railway network carrying capacity is given by the concept of system theories and transport demands, and relative study at home and abroad. based on the idea of systems engineering, the relative integrated concept of transport program is put forward, such as cargo-load planning, unload planning, and train flow path, and so on. the relationships between these transport programs are analyzed, and its influence on carrying capacity is pointed. when we optimize the car flow routing in railway network, the base is often the shortest path, but the shortest path is restricted by line and loading-unloading plan. based on the analysis of car flow routing, an optimization model of transport program, with the minimum cost taken as optimization objectives, was built according to the effective use of network carrying capacity, car flow routing and train program, and connects car flow organization with train flow organization effectively.key words: railway network， carrying capacity， transport program， car flow routing1 introductionas the competition among the various modes of transport, building a developed comprehensive railway network, developing potentialities, creating a good transport operating efficiency, improving network carrying capacity rapidly and increasing income to the utmost, are the main tasks of railway great-leap-forward development. although there are various measures to improve transport capacity, in summary, they are reconstruction measure and technical and organizational measure. choosing the most effective measures to improve transport capacity is a very important but complex task. organization of the train flow of railway network is a very strong foundation for an overall scheme. various transport programs are inter-related by the media of the fee of transport flow, the capacity of lines and equipments of station. therefore, the study of the relationship between the optimization of network transport program and transport capacity is significant for the improvement of railway network transport organization efficiency.2 overview of transport program 2.1 concept of transport programthe overall organization of the railway transport work daily to ensure the completion of the monthly task of a comprehensive plan for the carriage of goods, referred to as transport program is a comprehensive monthly on transport arrangements for the deployment and co-ordination.generally speaking, transport program includes freight transport, train, locomotive work programs as the main three parts and line construction, terminal and station work programs according to demands. an organic whole plan is based on the connection among every links. each links in transport production, such as freight traffic source, freight flow investigation, freight flow organization, train flow organization, train formation and running, locomotive traction, and so on, should be arranged comprehensively and systematically according to the transport program.freight transport work program is a comprehensive plan of freight and train flow organization, which stipulates specifically daily car loading plan in every ten days, all kinds of through train and groups-loading car plans and arrival loaded car plans, tight coupling transport production plan and train formation plan. train work program is a plan of the running of various trains, which organizes car flow into train flow in the best way and chooses proper train path for different trains. locomotive work program is a locomotive running plan, which arranges locomotive working diagram and the number of the supply locomotive basing on train work program and locomotive utilization mode. line construction program is a plan of line construction. terminal and station work program is a plan of make-up, break-up, taking-out and placing-in plan of train set and terminal transfer train running plan, which coordinates the work between district and terminal.2.2 basis of transport program making and significanceaccording to freight and car flow determined by monthly freight traffic plan and technical indices for freight traffic plan, on the base of freight traffic source, transport program is making according to the demand of freight train formation plan and train diagram and determining train running plan and locomotive operation plan meanwhile. it is the basis of daily transport operating plan making.making and carrying out of transport program and finding the rule and character of freight and car flow are helpful for coordinating the relationship of traffic volume and capacity and improving the cooperation between every link, level and area in transport production, so that every department of railway will work coordinately. at the same time it can help use locomotives, trains and other transport equipment economically, find the contradiction and bottle neck in transport production, take the contradiction scientifically, develop potentialities to the utmost, increase the efficiency, achieve the predictability and planning, realize coordination, balance work, rational transport and through traffic, so that it can ensure the faster, better and more economical completion of transport tasks. the key point is how to use line carrying capacity and station resorting capacity effectively and find the most economical program to satisfy the traffic volume demand, in this way the transport capacity will be improved effectively. also, this is the keystone of this paper.2.3 the relationships between the parts in transport programtransport program is a scientific arrangement of time and space, focusing on economic benefits. the schematic diagram of traffic organization process is shown in figure 1. to purse global optimization, it needs four combinations. they are the combinations of transport process and production process, freight flow and car flow, car flow and train path, train path and locomotive routing. the first two are the reflection of freight transport work program and the basis of transport program. the quality of freight transport work program has a direct impact on the quality of train work program and locomotive work program. the combination of car flow and train flow, which is the core of transport program, tightly couples freight transport work programs and train diagram and arranges the use and repair of locomotive economically, is reflected in train work program. the combination of train path and locomotive routing, which is the driving force of transport program, the successor of train work and the guarantee of the realization of freight transport work program, is reflected in locomotive work program. various transportation programs are mutually complementary, each doing its own duty throughout the entire transportation process. only in the view of system thought, can transport program take full advantage of equipment, accelerate the delivery of goods, reduce transport costs and obtain the system optimization.adjustmentfreight traffic sourceloadingunloadingloaded carempty carfreight transportation work programcar flowtrain flowtrain work programlocomotive work programmake-upbreak-uptrain diagramadjustmentfigure 1. the schematic diagram of main transport organization processas shown in figure 1, flow and line must be connected, so as goods, car and locomotive. train operation must be in accord with train diagram, which is the key and the guarantee of train crossover and locomotive supply.3 overview of transport capacity3.1 the meaning of railway transport capacitycarrying capacity is defined as ,under the condition of certain technical equipment and organization of train operation method, the carrying capacity of railway fixture in unit time (usually a day and night) by the maximum number (of the number or columns).carrying capacity is calculated by line or section. transport capacity is defined as, under the condition of certain fixture, locomotive type and organization of train operation, in accordance with locomotive and staff situation, the maximum quantity of car and freight ton-kilometers that can be carried by railway in unit time (usually one year). transport capacity usually reflects the realization of carrying capacity, so the former is equal to or less than the latter.studying railway network transport capacity will help transportation management departments grasp the whole network transport capacity. working out the program of car flow organization that can coordinate the capacity of point and line through the integrated planning of network car flow routing is helpful for the right decision-making about network programming and reconstruction. railway network transport capacity dose not just simply total up the capacity of each subsystem. thus, isolated study of the capacity of point or line has great limitations and will be one-sided. to provide a reasonable analysis and evaluation methods, it has yet to be studied and deepened systematically from conceptual, theoretical system and calculation methods aspects.3.2 influencing factors of railway transport capacity from its definition, we can see elements determining railway transport capacity as follows: certain types of locomotives and trains, fixture, existing members of crew and organization of train operation. railway transport capacity is mainly influenced by equipment, transport demand, car flow routing, train formation plan, train running plan, loading and unloading plans and a variety of random factors (other cause effective transport capacity loss of system).(1)equipment contains fixture, such as power supply equipment, line, station yard, bridge and tunnel, signal, etc, and move equipment, such as locomotives, cars, electricity, etc. (2)the use and organization of technical equipment is in the following aspects: existing transport programs, train formation plan are out of line with the actual transportation production situation and not be revised timely according to the use of new lines, equipments and technology and the change of transport market.after substantially accelerate the passenger trains speed, the difference between passenger trains and freight trains increases, so capacity calculation should be re-studied based on a reasonable proportion of passenger and freight trains.car flow adjustment is not flexible and transport organization of train spacing point, restriction point and district is not proper, resulting in increased number of serviceable cars held kept and one-way traffic overstock problem.unreasonable locomotive adjustment and unclose connection between trains and locomotives work plan result in more light locomotive running and transport capacity waste. the existing locomotive routing is not suited to the change of locomotive-type and traffic demand, for example, arm locomotive routing in certain sections causes frequent inspection of locomotives when arriving at depot and increases the burden of terminal throat and arrival and departure track of marshalling station.construction organizations are not standardized. integrated sky-light redemption rate is not high. the phenomenon, like no construction in important time, extension of slow running distance and construction delay, occurred frequently.3.3 network overall transport capacity improvement measuresalthough there are various measures to improve transport capacity, in summary, they are reconstruction measure and technical and organizational measure. the reconstruction measures include reasonable work-division, specialized freight station, reasonable adjustment of work in marshalling station and decrease the number of district station. in the aspect of transport production organization:(1)optimization of train formation plan. it should further optimize the work division of marshalling station, maximize the organization of through trains, reduce the times of restoring, strengthen technical station operating organization, grasp accurately the car flow and reduce the wrong make-up trains. actively organize technical through train, through train originated from one loading point and through train originated from several adjoining loading points and operation full-axis, full-length and heavy haul trains and reduce the resorting proportion of district station and marshalling station.(2)optimize car flow routing and improve the overall transport capacity. according to carrying capacity of parallel path, optimize and adjust car flow routing, focusing on car flow in capacity-strained sections and achieve most optimum distribution of resources under the existing condition. by plan the capacity of newly-built railway and existing railway as a whole, making busy trunk line unblocked and making full use of wing lines, the railway network capacity will be used efficiently.(3)increase tonnage of traction, static load of car and speed. on the premise of safety, increasing tonnage of traction, static load of car and speed reasonably will increase the density of passenger and freight transport and make up for capacity density. at the same time, on premise of transport safety and order, it is the fastest way of capacity expansion that selectively increasing the static load of certain cars according to the structural characteristics of different types and the actual state of technology when there is a serious shortage of empty car and transport capacity tends to saturation.(4)optimize programs of collection, distribution and transportation; improve efficiency in the use of locomotives and cars. the measures are as follows: improving efficiency of locomotive utilization by conformity of locomotive routing, strengthening organization of locomotive power, paying attention to locomotive organization in key sections, optimizing the running program of trains and locomotives, organizing the joint of trains and locomotives work plan, reducing the time that locomotive stay in depot and light locomotive running, ensuring sufficient shunting locomotives by reasonable arrangement, improving the quality of shunting operation plan, increasing and adjusting the locomotive servicing place, accelerating the speed of shunting locomotives and reducing non-productive wait time.(5)strengthen the construction organization. put integrated skylight maintenance into effect, adhere to the points according to plan, improve the construction redemption rate. strengthen the coordination between the transport departments, strive to achieve multi-purpose. equipment maintenance department should raise the level of organization and minimize disruption to transport.(6)strengthen loading and unloading organization, pay attention to freight station construction and improve the capacity of loading and unloading operations. enhance information collection and feedback, pay attention to supply dynamic, insist on the principle of focusing on focal point, use unloading car and close range empty car as many as possible, rational use of empty car resources. according to unloading capacity and the situation of receiving loading car, we should make a balanced shipment, actively organize the freight traffic source of non-restricted section and improve car utilization efficiency.4 optimization of transport programrailway network transport capacity limits every transport program making, which is the constrained condition of train flow path, train work program and locomotive routing. at the same time the railway transport network capacity is affected by train flow path, train formation plan and construction programs, etc. the train flow path also relates with loading and unloading plans, empty adjustment programs, train formation plans and pivot points in network. it is so complicated that we need to sort out their relationships and make clear of goals and conditions.4.1 analysis of railway network running program optimizationcar flow routing is an important factor in reflecting transport demand and one of the key links which will affect the overall effective transport capacity. car flow routing optimization is the possible simple organization method of determining each car flow routing resulting in the least running kilometers under the conditions of given network and traffic flow. railway network environment refers to the layout of railway network and the carrying capacity of stations and section. between two stations in the network, there are a number of paths to choose. reasonable car flow routing cam take advantage of existing equipment and improve the railway transport capacity.car flow routing and train formation plan are closely related. their relationship is mutually conditional and constraint. while making train formation plan, we should first determine the direction of traffic between the various pivot points according to car flow routing and then look for the best resorting programs; in daily adjustment of car flow, some of the measu