Key Technologies Research On Capacity Improvement Of Heavy Haul Special Freight Line

In recent years, planning and construction of large capacity coal transportation corirdorsare been continuously strengthened in our country. New line construction has beenincreased as well as the upgrading of existing heavy haul coal special lines. Heavy haulrfeight special line aims to largely increase the transportation eiffciency of rfeightespecially coal. The further strengthening of its own capacity relies on the study andapplication of heavy haul related key technologies. The paper selects a number ofadvanced technologies in the ifeld of heavy haul with the combination of developmentlevel and technology development direction of heavy haul railway in our country atpresent, and studies their application in heavy haul rfeight special line and thestrengthening effects to line transport capacity.Firstly, the paper strengthens the conveying capacity of heavy haul rfeight specialline by developing high axle load rfeight cars rfom the perspective of increasing axleload. On the basis of C96type special gondola car for transport of coal, by making themost of the electric locomotive gauge in rolling stock upper gauges fo’r Chinas standardgauge railways, to expand car body section area and improve the axle load of coaltransport special gondola car to maximum reasonable level. The axle load of the newtype gondola car reaches32.3t and the weight per extended meter of the car is9.5t/m.Compared with C80and C96type gondola cars，the single car carrying capacity of thenew gondola car rises23tons and7tons respectively，and the capacity expansion effectis remarkable when operating trains marshaled by new cars.32.3t axle load heavy haultrain has a good adaptability with “quasi level3” rfeight special line, the adaptabilitywith "level2” rfeight special line is yet to be tested, and it is unsuitable for “ultra level1” line like Jinzhongnan railway corridor. The new gondola car’s gravity center heightof car loaded under the conditions of both full load and ofil volume reaches2057mm,which slightly exceeds the standard of2000mm.Use new type gondola cars to marshal and operate heavy haul trains to improveheavy haul transportation capacity. The axle load and formation length of train increase,which will lead to the increase of braking distance and then affect the tracking interval.Atfer adopting ECP braking technology, the braking distance of heavy haul train islargely reduced，which will have an obvious effect on capacity strengthening of rfeightspecial line. Using new type gondola cars to marshal20000t heavy haul combined train,then calculate emergency braking distance and full service braking distance in12%o long heavy down grade adopting Locotrol device or ECP system separately, and theminimum interval of1OOOOt,15000t and20000t heavy haul trains tracking one anotherin ifxed automatic block section is between6min and8min atfer adopting ECP, which isshortened by2min generally compared with Locotrol device. ECP brake technologysignificantly improves carrying capacity of line section.The paper further studies the feasibility of using moving automatic block in heavyhaul rfeight special line and its strengthening to capacity. Introduce the fundamentals ofmoving block system and train tracking interval model under MAS (Moving automaticblock system). Calculate the tracking interval of20000t heavy haul combined train inMAS section atfer using ECR When adopting Locotrol device, the tracking interval of20000t train in MAS section is7min, which is shortened by3min compared to FAS(Fixed automatic block system). When adopting ECP system, the tracking interval inMAS section is5min，which is2min shorter than that of FAS. The combination of MASand ECP makes the train tracking interval be approximately decreased by half.The paper discusses the feasibility of application of road car-following model intrain traiffc flow on heavy haul rfeight special line. Analyze the characteirstics of trainfollowing. Build train following model of heavy haul rfeight special line according tolinear rule based on simpliifed linear car-following theory. Introduce the notion of lfowand density，build lfow-density relation model of following train flow to descirbe thedynamic change of section capacity. Use kinetic wave theory to study the characteirsticsof following train lfow and the wave propagation characteirstics and capacity losscaused. When the line is in planned construction, train departure interval can beadjusted to control train flow and optimize train trajectories in order to eliminate kineticwaves and reduce capacity loss.Finally, the paper optimizes the train operation plan of technical station in heavyhaul rfeight special line to reduce the total technical operation time of all trains operatedin one day and night in order to strengthen the capacity of the whole line by increasingcapacity coordination between station and section. Analyze the occupation situation of1OOOOt,15000t and20000t trains on arirval-departure tracks and station throat oftechnical station in the combining operation process. Then establish an objectiveprogramming model to meet the constraint condition of different target annual rfeightvolume with the goal of minimum average train technical operation time in thecombination station，and use LINGO sotfware to calculate the specific operationproportion. Under certain conditions and assumptions, the train operation proportion of combined station is obtained. When the target volume is under300million tons, alllOOOOt trains will meet requirements. When the target volume continue to increase, theproportion of lOOOOt trains falls while the proportion of20000t trains increases, and theproportion of15000t trains firstly increases and then decreases. When the target volumereaches the maximum value of470million tons, all20000t trains are needed.