3 Related Fields to Capacity Research AnalyticsData miningNetwork optimizationQueuing theoryRegression modelingRisk modelingSimulationUtility models
4 Railroads’ Capacity History 19th and early 20th century: Great expansion of railroadsWorld War I: War traffic brought network to standstill due to insufficient capacity due to inefficient operations,1920s: Relative balance between capacity and traffic levelsGreat Depression: Loss of traffic led to excess capacityWorld War II: Congestion from war trafficAfter WWII: Overcapacity as passenger and freight traffic declinedCurrent: Growth in traffic and market power has permitted railroads to spend substantial amounts to remove choke points
5 More Demands on U.S. Railroad Network Freight GrowthLow CostTransportationReliabilityIntercity Passenger TrainsEnvironmentCambridge systematics study of 2030 freight traffic without improvementsCommuter ServiceCambridge Systematics. (2007). National Rail Freight Infrastructure Capacity and Investment Study.
6 Problems of Capacity Shortages Inability to handle more trafficDecreasing level of serviceDiminished ability to recover from a disruptionLimited windows for track maintenanceCrew time limitationsIncrease time in yardsIncrease cycle timesAll of these increase costs
7 Railroads are Capital-Intensive The rail industry is the most capital intensive industry when compared to other capital-intensive businesses.There are numerous needs for capital dollars to maintain and expand our network to handle growth.
8 Railroads Own Expensive Assets Track Construction ≈ $2,500,000 to $4,500,000 per mile171,513 track milesLocomotives ≈ $1,800,000 each23,732 locomotivesRail Car ≈ $70,000 each580,635 railroad owned freight cars
9 Capacity Can Be Measured Anywhere Transportation NetworkRailroad NetworkDivisionSubdivisionYards & TerminalsIndustry Facilities
10 Types of CapacityPractical Capacity: Ability to move traffic at an “acceptable” level of serviceEconomic Capacity: The level of traffic at which the costs of additional traffic outweighs the benefitsEngineering Capacity: The maximum amount moved before the system ceases to functionUltimate Capacity: The system has ceased to function and all signals are redKahn, Ata M. Railway Capacity Analysis and Related Methodology. Ottawa, Print.
11 What Should “Capacity” Measure? Amount MovedUtilizationReliabilitySogin, Samuel L et al. “Measuring the Impact of Additional Rail Traffic Using Highway & Railroad Metrics.” Proceedings of the 2012 Joint Rail Conference. Philadelphia, 2012.
12 Railroad Capacity Metrics Amount MovedReliabilityUtilizationTrainsCarsTonsRevenue TonsPeopleTEUs(Per Year)(Per Day)(Per Hour)(Per Peak Hour)Distribution of Arrival TimesAverage DelayStandard Deviation of DelayOn Time PerformanceRight Car Right TrainCrew ExpirationsVelocityDwell time in TerminalsBlocking TimeSignal WakeTrain Miles/Track MileCycle TimeSogin, Samuel L et al. “Measuring the Impact of Additional Rail Traffic Using Highway & Railroad Metrics.” Proceedings of the 2012 Joint Rail Conference. Philadelphia, 2012.
14 Meet and PassSingle track poses significantly more challenges for capacityNo longer simply limited by train spacingMust consider “meets” of trains traveling in opposite directionThese impose constraints on schedule
19 Track Configuration Number of tracks Siding length Siding spacing (distance & time)Crossover spacingSingle crossoversUniversal crossoversParallel crossoversLength of bottleneck sectionGradeCurvature
20 More track can lead to smaller delays ST, siding every 21.4 milesbidirectional running, DTDelay (hours)directional running, DTVolume (trains/day)Kahn, Ata M. Railway Capacity Analysis and Related Methodology. Ottawa, Print.
21 Two Separate Single Track Lines High-volume routeEach railroad was operating single track with passing sidings between St. Louis and TexasElimination of bi-directional running was one of the big pay-offs in the UP-SP merger
22 Directional Running After Merger Eliminate “meet delay”
23 Maintenance Factors Track quality Inspection frequency Track failure frequencyMaintenance schedulingLengthFrequencySurfacing cyclesTie life (Concrete or wood)Rail lifeDynamic defect detection of rolling stock & track
24 Train Types Dynamics Acceleration Braking Maximum speed Horsepower to trailing to ratioDistributed powerCargo CapacityNumber of railcarsNominal capacity of railcarsHeight, width
25 Influence of HPT on Acceleration Distance -3.69--3.08--2.46--1.84--1.23--0.61-7,150 ton train
26 Train Interactions Number of trains per day or per hour Traffic mixturePriority differentials: Sacrificing the performance of one train type (freight) to preserve the on time performance of a preferred train type (passenger).Speed differentials: Train that operate at different speeds that can cause passing conflictsSchedulingDirectional fleeting: Decrease meet delay by only operating in one direction for an intervalType fleeting (time windows): Decrease delays of different trains interacting with each other by separating the traffic type by time of dayConcentration of trains due to the railroad network design
27 The Impact of Different Type of Trains DestinationIntermodalUnitAmtrakManifestDistanceOriginTimeTime
28 Signaling Method of operation (YL, TWC, CTC) Presence of ABS (Automatic block signaling): Allows for closer train spacing and higher speedsSignal spacing: Gives information more frequently on the block occupancySignal aspects: Gives more accurate speed control to following trains allowing for tighter spacingPresence of power switches: Eliminates the need to stop to operate switchesAdvanced control systemsCab signalingMoving blockPTCMethod of operationYard limits (Restricted speed)Track warrant controlCentralized traffic control
29 Yards Length of yard leads Total time that yard processes use the mainlineCrew changesSize of receiving and departure yardsNumber of tracksLength of tracksMethod of operationYard limits (Restricted speed)Track warrant controlCentralized traffic controlKahn, Ata M. Railway Capacity Analysis and Related Methodology. Ottawa, Print.
30 Options to increase line capacity Operations options:Increase average speedReduce traffic peakingReduce the variability in speedReduce number of meets & passesIncrease length & weight of trainsInfrastructure options:Line (links):Add or lengthen passing sidingsAdditional tracksJunctions (nodes):Add classification tracksExtend yard linesImprove junction designGrade separation
31 Unlike highways, there is no standard railroad capacity model The complex nature of railroad operations and limited research funding has prevented a universal capacity model from being developedCurrently several different models are in use
32 Different Traffic Characteristics will change the Maximum Volume Acceptable Delay
33 Level of Service to measure Capacity Higher delays correspond to a lower level of service (LOS)Maximum theoretical volumes are never reached to increase level of service of trafficMetric:DelayAbril, M., Barber, F., Ingolotti, L., & Salido, M. (2008). An assessment of railway capacity. Transportation Research Part E: Logistics and Transportation Review, 44(5),
34 Railroad Capacity Models Computational IntensityAccuracyTheoreticalLowLow-mediumParametricMedium-highMediumSimulationVery highLow-highAnalyticalSimplest ModelsCan be computed manually for simple networksParametricIdentify critical parametric relationships and focus on the key elements of line capacityEstimates theoretical and practical throughputSimulationClosest representation of actual operationsData intensive, not practical for network modeling
35 Theoretical: Maximum Throughput Computation The maximum traffic flow that a rail line can accommodate under ideal conditionWhere:N = Number of trains per day1440 = Number of minutes in a dayHmin = Minimum headway (minutes)1440N=Hmin
36 Theoretical: Blocking Time Model DistanceMinimum Head WayTimePachl, Joern, and Thomas White. “Analytical Capacity Management with Blocking Times.” Transportation Research Board: 83rd Annual Meeting (2004)
37 Theoretical: Single Track Capacity (Poole) Calculated headway in single track with passesC = Capacity in trains per day1440 = Number of minutes per 24 hourst = Minutes to travel between sidingst/2 = Average dwell time waiting for opposing train to arrivem = Delay for each meet due to braking, entering the siding, running the length of the siding, leaving the siding and accelerating to full speed2 = number of trains per pairPoole, EC. “Costs--A Tool for Railroad Management.” (1962)
38 Poole Methodology Siding A Siding B Time 0 Time t Time t+m Time t+m+t/2Time 2t+m+t/2
39 Parametric ModelsParametric Model are based off statistical analysis of operating or simulation dataKey infrastructure and operating parameters are identified to predict a delay-volume curveAttributes includeAverage speedSpeed ratioPriorityPeakingSiding spacing and uniformityPercent double trackSignal spacing
40 CN Parametric Model Example Average Speed44.4 mphSpeed Ratio1.113Priority0.342Peaking1.727Siding Spacing7.77 milesUniformity0.49Signal Spacing0.93% Double Track50Krueger, H. “Parametric Modeling in Rail Capacity Planning.” Proceedings of the 1999 Winter Simulation Conference. Phoenix, Web. 21 May 2012.
41 Railway Simulation Tools Calculates train movements and makes decisions under the same rules as railroad dispatchersThey account for different equipment types, train consists, train handling characteristics, terrain and track conditionsCommon uses of Simulation Tools:Develop operating plansDiagnose bottlenecks and recommend schedule changesEvaluate various capital improvement scenariosAssess the impact of adding new trains to a network
42 Rail Traffic Controller Developed by Eric Wilson from Berkeley Simulation SoftwareEmulates a dispatcher controlling train movements across a network based on train priorityIntegrated train performance calculatorInputs: track, signals, trains, and scheduleOutput: delay, average velocity, on time performance
47 Scheduling Fleeting Express scheduling Type: Reduce delays due to different train types operating on the same lineDirection: Reduce delays on single tracks lines by reducing the meet delayExpress schedulingDecrease travel time by bypassing intermediate station and terminalsMinimize conflicts with trains in the same direction
48 Existing ScheduleTrain #300302304306308314316318320322324326328330AM/PMAMKenosha–5:516:176:537:157:51Winthrop Harbor5:596:257:027:237:59Zion6:036:307:067:288:04Waukegan4:204:585:265:546:136:397:097:207:377:508:12North Chicago5:015:295:586:166:437:127:247:417:538:15Great Lakes5:056:026:467:167:277:588:18Lake Bluff4:285:105:356:066:226:507:327:468:22Lake Forest4:315:135:396:106:266:547:368:25Fort Sheridan5:165:436:146:316:597:407:558:07Highwood5:195:466:347:438:10Highland Park4:385:225:506:206:377:057:317:548:018:33Ravinia5:255:536:236:417:358:14Ravinia ParkBraeside5:275:556:447:578:17Glencoe4:435:306:286:477:398:008:208:39Hubbard Woods5:336:017:187:428:038:23Winnetka4:475:366:047:217:487:568:268:43Indian Hill5:386:366:557:338:068:29Kenilworth5:406:086:386:578:088:318:46Wilmette4:505:426:427:388:48Evanston Central Street4:535:456:457:348:138:358:51Evanston Davis Street4:565:496:487:448:118:388:54Evanston Main Street6:196:517:478:40Rogers Park5:028:44Ravenswood5:076:297:018:098:50Clybourn7:077:198:028:168:378:569:06Ogilvie Transportation Center5:236:157:177:308:418:479:059:15B.C.Sogin, Samuel L, Brennan M Caughron, and Samantha G Chadwick. “Optimizing Skip Stop Service in Passenger Rail Transportation.” Proceedings of the 2012 Joint Rail Conference. Philadelphia, Print.
49 Genetic Algorithm Schedule Train #304306308310312314316318320322324326328330AM/PMAMKenosha6:006:056:116:226:316:386:456:537:007:077:147:217:287:36Winthrop Harbor6:126:17-6:436:506:577:057:127:197:337:48Zion6:166:216:266:476:547:017:097:167:237:297:377:52Waukegan6:256:306:356:567:037:107:187:257:327:387:468:01North Chicago6:406:487:548:06Great Lakes7:59Lake Bluff6:497:457:508:038:14Lake Forest6:426:526:597:538:17Fort Sheridan7:277:428:08Highwood7:588:10Highland Park6:587:207:267:317:397:558:23Ravinia6:467:087:347:498:15Ravinia ParkBraeside7:358:25Glencoe7:447:518:058:188:28Hubbard Woods7:138:128:21Winnetka7:068:028:248:32Indian Hill7:568:26KenilworthWilmette7:047:118:198:298:36Evanston Central Street7:248:39Evanston Davis Street7:177:578:118:35Evanston Main Street7:307:438:278:43Rogers ParkRavenswood8:42ClybournOgilvie Transportation Center8:168:318:378:448:548:59B.C.Sogin, Samuel L, Brennan M Caughron, and Samantha G Chadwick. “Optimizing Skip Stop Service in Passenger Rail Transportation.” Proceedings of the 2012 Joint Rail Conference. Philadelphia, Print.
50 Types of Operations Scheduled Hold-For-Traffic Hybrid Systems All train movements are planned and followed preciselyCommuter, inter-city passenger trainsSome freight trainsHold-For-TrafficWait for the necessary traffic threshold to run a trainGrain, coal and other bulk trainsHybrid Systems
51 Economics Project selection models Determining the cost of congestion Determining the capacity of a railroad lineBase train equivalenceOther operating metrics
52 Economics of Railroad Capacity Marginal RevenueMarginal Cost
53 Research Needs Models that capture yard-mainline interaction Predicting the impact of higher speed passenger and freight trains on the same corridorCreating new theoretical & parametric models
54 References (1) Abril, M, F Barber, L Ingolotti, and MA Salido “An assessment of railway capacity.” Transportation Research Part E: Logistics and Transportation Review 44 (5):S Chultz A Ndreas T Anner, and Ralf Bornd “An Auctioning Approach to Railway Slot Allocation An Auctioning Approach to Railway Slot Allocation.” Management 45 (October):Cambridge Systematics National Rail Freight Infrastructure Capacity and Investment Study.Carey, M “Stochastic Approximation to the Effects of Headways on Knock-On Delays of Trains.” Transportation Research Part B: Methodological 28 (4):Dingler, Mark, Amanda Koenig, Sam Sogin, and Christopher P L Barkan Determining the Causes of Train Delay. In AREMA Annual Conference Proceedings. Orlando.Dingler, Mark, Yung-Cheng Lai, and Christopher P.L. Barkan “Impact of Train Type Heterogeneity on Single-Track Railway Capacity.” Transportation Research Record: Journal of the Transportation Research Board 640 (2117):Gorman, Michael F “Statistical Estimation of Railroad Congestion Delay.” Transportation Research Part E.Harrod, Steven “Capacity factors of a mixed speed railway network.” Transportation Research Part E 45 (5):Ireland, Phil, Rod Case, John Fallis, and Jason Kuehn “Perfecting the Scheduled Railway : Model-Driven Operating Plan Development.” System: 1-28.Kahn, Ata M Railway Capacity Analysis and Related Methodology. Ottawa.
55 References (2)Krueger, H Parametric Modeling in Rail Capacity Planning. In Proceedings of the 1999 Winter Simulation Conference, Phoenix.Leilich, Robert H Application of Simulation Models in Capacity Constrained Rail Corridors. In Proceedings of the 30th conference on Winter simulation,Lu, Quan, Maged Dessouky, and Robert C Leachman “Modeling Train Movements Through Complex Rail Networks.” Computer 14 (1):Martland, Carl D, Patrick Little, and Joseph M. Sussman “Service Management in the Railroad Industry.” Transportation Research Board.Mattsson, LG “Railway capacity and train delay relationships.” Critical Infrastructure.Pachl, Joern Railway Operation and Control. 2nd ed. Mountlake Terrace: VTD Rail Publishing.Pachl, Joern, and Thomas White “Analytical Capacity Management with Blocking Times.” Transportation Research Board: 83rd Annual Meeting.Petersen, ER “Design of single-track rail line for high-speed trains.” Transportation Research Part A: General 21 (1).Poole, EC “Costs--A Tool for Railroad Management.”
56 References (3)Preston, John, Graham Wall, Richard Batley, J Nicolás Ibáñez, and Jeremy Shires “Impact of Delays on Passenger Train Services.” Transportation Research Record: Journal of the Transportation Research Board (2117):Sogin, Samuel L, Christopher P.L. Barkan, Yung-Cheng Lai, and Mohd Rapik Saat Measuring the Impact of Additional Rail Traffic Using Highway & Railroad Metrics. In Proceedings of the 2012 Joint Rail Conference. Philadelphia.Sogin, Samuel L., Christopher P.L. Barkan, and Mohd Rapik Saat Simulating the Effects of Higher Speed Passenger Trains in Single Track Freight Networks. In Proceedings of the 2011 Winter Simulation Conference, PhoenixSogin, Samuel L., Brennan M Caughron, and Samantha G Chadwick Optimizing Skip Stop Service in Passenger Rail Transportation. In Proceedings of the 2012 Joint Rail Conference. Philadelphia.Vromans, Michiel J C M, Rommert Dekker, and Leo G Kroon “Reliability and heterogeneity of railway services.” European Journal Of Operational Research 172:White, Thomas Examination of Use of Delay as Standard Measurement of Railroad Capacity and Operation. In Transportation Research Board: 85th Annual Meeting. Washington, D.C.
58 Copyright Restrictions and Disclaimer Presentation AuthorSamuel L. SoginGraduate Research AssistantRail Transportation and Engineering CenterCivil & Environmental Engineering DepartmentUniversity of Illinois at Urbana-Champaign1203 Newmark Civil Engineering Lab, B118Urbana, IL(847)It is the author’s intention that the information contained in this file be used for non-commercial, educational purposes with as few restrictions as possible. However, there are some necessary constraints on its use as described below.Copyright Restrictions and Disclaimer:The materials used in this file have come from a variety of sources and have been assembled here for personal use by the author for educational purposes. The copyright for some of the images and graphics used in this presentation may be held by others. Users may not change or delete any author attribution, copyright notice, trademark or other legend. Users of this material may not further reproduce this material without permission from the copyright owner. It is the responsibility of the user to obtain such permissions as necessary. You may not, without prior consent from the copyright owner, modify, copy, publish, display, transmit, adapt or in any way exploit the content of this file. Additional restrictions may apply to specific images or graphics as indicated herein.The contents of this file are provided on an "as is" basis and without warranties of any kind, either express or implied. The author makes no warranties or representations, including any warranties of title, noninfringement of copyright or other rights, nor does the author make any warranties or representation regarding the correctness, accuracy or reliability of the content or other material in the file.
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