Coordination Optimization Study Of Train Break-up And Make-up Scheme Based On Hard Time Windows At Railway Marshalling Yard

During the railway transport production, marshalling yard has served a very important role, is the most basic production unit in railway,that will undertake to break up the freight train coming from different directions in the convergence section and reassemble into a new freight train sent to train section.The marshalling yard must be coordinated between the various jobs in order to ensure its normal operation. Which job is the key to de-compile the entire job of marshalling, the poor coordination of breaking up and marshalling operation,will make yard with car-free or vehicles piled, and affect the whole work of production dispatching. In view of this, the railway marshalling yard in transportation and production scheduling command focused on solving the problem is the rational organization of disintegration and marshalling of trains, so the scheme of train marshalling and dissoluting can be coordinated.On the basis of many domestic and international research literature about coordination of operations relating to Marshalling, this paper described the marshalling yard with the job and various equipment as well as content and preparation process of Stage Plan, Analyzed and discuss the whole factors and basic conditions of coordination between arrival, disintegration, marshalling,departure and the whole station.By studying the trains of arrival and departure at break-up and make-up time, the relationship of train break-up and make-up sequence was respectively researched and analyzed, the condition by which train break-up and make-up sequence could be adjusted was obtained,that provided a theoretical basis of coordination in the scheme of train marshalling and dissoluting.In this paper, based on the different hard time windows constraints of traction weight and converted length of train, considering constraints of arrival,break-up,assembling,make-up and departure, the optimization model for coordination in the scheme of train marshalling and dissoluting was established. The objective of this model was set to maximize the number of fully loaded departure train and minimized the waiting time of vehicles in marshalling yard.In the application of ant colony algorithm to solve coordination problems in the scheme of train marshalling and dissoluting based on hard time window, according to the basic principles and characteristics of the algorithm, combined with characteristics of the mathematical model established in this paper, the following four aspects of the ant colony algorithm had been improved: Firstly constructing collection that were defined by the enable-break-up set,waiting-break-up set and selected-break-up set for arriving trains; Secondly improving the search rules state that was based on "roulette strategies" and "random probability" and used to prevent algorithm prematurely convergence to local feasible solution; Again defining the concept of "matching rate" to promote the scheme of train dissoluting as much as possible to take care of marshalling scheme; Lastly updating strategy of pheromone in the ant colony algorithm that is the intensity of pheromone was closely related to the number of fully loaded departure train.Finally,this paper had designed the specific example based on the proposed model to analyze the problem, and solved it by the improved ant colony intelligent algorithm and software platform using C # programming, and analyzed algorithm parameter values for the influences of the issue objectives. The example shows that the algorithm designed can narrow the size of marshalling assignment, choose a more reasonable train assignment results so that the scheme of train marshalling and dissoluting can be coordinated, and thus provided theoretical support for the realization of comprehensive coordination between each jobs in marshalling yard.