esg uqam cirrelt - crt · cirrelt intermodal transportation teodor gabriel crainic esg uqam &...

CIRRELT

Intermodal Transportation

Teodor Gabriel Crainic

ESG UQAM&

CIRRELT - CRT

2© Teodor Gabriel Crainic 2006

Plan

What are we talking about?Container-based intermodal transportationSystem design (location)Fleet Management (empties)Perspectives


What are we talking about?


Intermodal Transportation

Simple and straightforward definition:Movement of a person or a load by a sequence of at least two transportation modes, the transfer from one mode to the next being performed at a (intermodal) terminalE.g., Door-to-door transportation of containers

Over long distancesOrigin → “land” transport → port → container ship → port → “land” transport → destination


A “Strict” Definition

Movement of goodsOne and the same loading unit or vehicleA chain ofSeveral transportation modes (services)

CoordinationInteractions

Intermodal terminalsNo handling of the goods themselves

Door-to-door service European Conference of Ministers of Transport (1993)


A More General Definition

Movement of goodsA chain (network)Several transportation modes (services)

Coordination (more or less) Interactions

Intermodal terminals“Door-to-door” service


Many Things to Many People

Major instrument for E.U. policy aimed at switching freight from trucks & highways to more environment-friendly modes (rail, water)Dedicated rail services (subdivisions) to move large volumes of containers/trailers over long distances: the trans-continental “land bridges”Container transportationConsolidation carriers: local & long-haul operations, several long-haul types of services, with/without use of external services


Many Things to Many People (2)

Uncontainerized cargoCourier (express) services National planningCity LogisticsTerminal (ports, airports, …) planning and operations


Scope of Presentation

Container-based intermodal transportationIllustrative planning/operations management issuesOperations research models and methods

A very young fieldNo definite answersAn open invitation to join in !! ☺


Plan



Intermodal Transportation – Containers

AdvantagesReduced cargo handlingIncreased security regarding damage and lossIncreased standardization of transportation and transfer equipmentIncreased automation of terminal operations

⇒Cost reduction, more efficient door-to-door transportation

Sustained growth


Evolution of Container Traffic (Koh and Kim 2001)

5.8254.6200310.6280.02004

Growth rate (%)Container traffic (M)Year

8.6 304.02005

3.9240.620022.8 231.62001

10.9 225.3200010.0 203.219994.2153.519979.8137.21995

12.5 113.21993


Intermodal Transportation – Containers (2)

Lifeline of world-wide trade and economyIncreasingly larger container ships for inter-continental transportation (liners)

These cannot berth at all portsIt is not economical to stop at many ports

Container mega portsNew coastal navigation feeder services (“regular” ships): mega ports and huge liners ↔ regular ports⇒A new link in the multi-modal chain

“New” long-distance rail services (double-stack)


Intermodal Transportation – Containers (3)

Asia (Hong Kong, Singapore, …) to America or Europe:Origin → truck → port → large container ship (liner) → mega port → “small” container vessel → port →truck/rail/river → destinationContainer port terminal transformations for increased efficiency in loading/unloading operations and exchanges with land carriers

New terminals / Enhancement of existing onesAutomationIntelligent Transportation Systems


Notes

Container intermodal transportation (& express courier / post services)

Customer: Customized serviceOperator(s): Hub-and-spoke network with consolidation

All long-haul transportation must address the issue of empty vehicle repositioning

Trade is unbalanced⇒Vehicle flows as well !!

Tight fleet size? Long distances?


Plan



System and Service Design

Strategic decisions – System DesignLocate (intermodal) terminalsDirect/indirect customer (zone) servicePort/terminal dimensioning

Number of berthsSize of storage spaceType & number of various equipment types

Facility & service abandon, …


System and Service Design (2)

Tactical decisions – Service DesignRoutes served (routes, stops, mode, equipment, …)Service frequency & scheduleCargo routingTerminal workloads

Container port terminal equipment assignmentTo sea-side and land-side operations

Not many contributions for container transportation


System Design

Not many contributionsTactical or operational models to evaluate strategic strategiesPorts: queuing, simulation

Discrete location modelsConsolidation / hub terminals

Network design + locationSelect direct services/links

Aim to capture economies of scale associated to consolidation of freight


System Design (2)

Location of facilities (terminals)Production-distributionHub locationLocation with balancing requirements


Location with Balancing Requirements

Land part of an intermodal container transportation system (may be generalized)Use in-land container depots for more efficient operations and reduced empty travel


“Traditional” Operations

Importingcustomer

Exportingcustomer

LoadedEmpty


Operations with In-Land Depots

Importingcustomer

Exportingcustomer

LoadedEmpty

Empty balancing


Location with Balancing Requirements (2)

Loaded movements are “profitable”Empty movements are not

Customer to depot: Return movementSupply of empties

Depot to customer: Demand satisfactionDemand for empties

Depot to depot: Repositioning of empty containers due to unbalances in supply/demand


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Plan

What are we talking about?Brief overview of freight transportationContainer-based intermodal transportationSystem design (location)Fleet Management (empties)Perspectives


Operational Planning

Resource managementCrewsVehiclesPower (engines, etc.), and so on

Allocation – dispatching, schedulesMake sure the required resources are where they need to be when they need to be thereBe efficient !(Satisfy demand, achieve economic and service objectives, implement plan, obey laws, policies, …)


Issues

Trade is unbalancedMoving goods results in unbalanced distribution of resources: crews, vehicles, etc.One needs to reposition resources for use in the following periods

Regular operations (if possible)Balancing operations (vehicles, power units, …)Crews travelling as passengers

The demand in following periods is a forecast


Other Operational Issues

Real-time dispatchPacingReal-time routing adjustment…


Consolidation Transportation

Transportation plan “guides” operationsIt includes guidelines for repositioning (it should …)“Indicative” schedules: Ad-hoc (real-time) procedures“Regular” demand planning: Short-term and real-time adjustment of plansScheduled operations: Repositioning must follow and “feed” schedules + real-time adjustmentWell-defined crew (personnel) schedules


Customized Transportation

No plan !!Dynamic management and control of resources: routes, schedules, fleets, personnel, etc.Uncertainty plays important role

DemandTravel timesService times at customers and terminalsWeather, …


The Empty Vehicle Repositioning Problem

Surpluses and deficits of empty vehiclesObserved at terminals “at the end” of the dayComputed with respect to the next period demand

Need to reposition for the next periodHow many vehicles (of what type) to move from a surplus location (origin) to a deficit location (destination)?

Much more decision freedom than in loaded transportationA cost activity with “no” profit


History

Transportation model – static and deterministicKnown surpluses and deficits – No uncertaintiesNo (not important) travel time impact – StaticArrival times known (certain prediction)

All travel, loaded and empty, occurs during the same period

Single or fully substituable resources (vehicles)For certain LTL types, tactical planning, …


History (2)

Deterministic, multi-period transshipment modelDifferent movements require different travel timesVehicles become empty at different moments (customer release times) Demand varies in time …The dynamic characteristic of the system represented through (dynamic, time-dependent) space-timenetworks


Space-Time Networks

Nodes: Facilities – terminals, customers, etc. – at given time periods

A physical point is repeated at each period & activity Arcs: Movements in space and time

Independent, e.g., a truck moving by itselfGrouped, e.g., containers on flat cars (rail) or in a shipHolding decisions (vehicles or cargo)


Space-Time Network (Simple)T

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Current period Future periodsInventory (holding) arcRepositioning arc


Space-Time Network

Loaded movementEnd of horizon

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Current period Future periodsInventory (holding) arcRepositioning arc


Challenges and Limitations

One may includeCapacitiesSeveral types of resourcesInventory costs

Stock out (rent, borrow, …)End of horizon value

Substitutions (and costs)Complex cost structures

Linear programming formulations with a few “complications”


Challenges and Limitations (2)

Planning horizon length? End-of-horizon? Rolling horizon

Everything is deterministicTimes (travel, terminal operations, customer, …)Future demand, etc.

UtilizationStrictly scheduled railways with bookings


The Uncertainty Factor

Times may varyDemand estimation is rarely preciseUnexpected demands and events Current decisions impact the future state of the system and future decisionsNeed to explicitly consider / model

Uncertainty – the stochastic nature – of the system and its environmentThe impact of current decisions on future system state and decisions


The Uncertainty Factor (2)

Stochastic formulations and solution methodsA complex field: General approaches and, often, custom-designed methods Active research fieldFormulations

General stochastic programming and solution methods :

Few efficient applications to transport problems



FormulationsRecourse formulations and rolling horizon methods

Nice application to regular-type systems (e.g., consolidation)

Stochastic formulation and solution strategies based on adaptive dynamic (linear) programming and decision/time-based decomposition

Time-Space multicommodity networksRecent developments with interesting results



Challenges of stochastic formulationsProblem formulation (!!)Resolution (!!)

PlusRepresentation of resources and attributesForecastsAvailability and reliability of dataValidation of models and strategiesImplementation and follow up


Container (Empty) Fleet Management

Major repositioning decisions over large geographical regions (e.g., inter-continental movements)

Similar to consolidation transportationAllocation of empty containers to customers

Similar to customized transportation Two applications in this talk

Allocation and management of a heterogeneous fleet of containers over a land zoneSingle-commodity dynamic container allocation for liner operators (regular ocean navigation lines)


Heterogeneous Fleet

Given region (continent)Loaded containers arrive (e.g., maritime network) to be delivered to customersEmpty containers arrive or leave to balance system-wide operations (demand)Customers empty containers that must be moved out Customers require empty containers for future loaded shipmentsOne must manage the fleet of containers for maximum profit, while satisfying demand


Heterogeneous Fleet (2)

Several types of containers (e.g., 20 or 40 feet, normal box, thermal, refrigerated, etc.)Substitutions allowed: conditions and costs“Massive” inter-depot balancing movementsDue-dates at some terminals (e.g., ship schedules)Time windows at customersDemand (at least part of) fluctuates in time and is forecasted onlyUnloading time at customer: UncertainTravel times may be uncertain as well


Heterogeneous Fleet (3)

Containers may be damaged partially (repairs) or totallyExternal sources (buy, rent) of empty containersCentralized empty container fleet managementLoaded movements not “managed” Associated problem: global management of the empty & loaded container movements together with vehicle routesA single model not computationally feasible ⇒hierarchical DSS


Main Movements(No Time/Container Type Specifics)

Harbour

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Depot kSupplycustomer

Demandcustomer

Externalpool ofemptycontainers


Formulations

Crainic, Dejax, Gendreau (93)Single and multicommodity deterministic formulationsA two-stage, restricted recourse single commodity, stochastic modelMulticommodity stochastic formulations may be defined


Formulations (2)

Space-time diagram Generalized network (substitutions)Multiple-period transportation arcsHolding arcs (depots)Inter-depot balancing arcs

Stochastic elementsDemand (of known and possible customers)Release time from supply customers

⇒Inventory levels⇒Import and export (border points, external pool)


Formulations (3)

Minimize total cost over the time horizonFlow conservation (over time and space, including access to external pool)

Supply at supply customersDemandContainer substitution

Depot (and port) inventories (each container type)Bounds on inter-depot balancing flows“End-of-horizon” restrictions (e.g., limits on “final”inventories)


Single Commodity Liner

Cheung and Chen 1998A container liner company offers regular service among a number of portsCarries loaded and, space permitting, empty containersShip schedules known and fixed1 ship / period between 2 portsDemand less than ship capacity1 container type


Formulation

Two-stage stochastic model Time-space network with random arc capacitiesMinimize the (expected) total costRolling-horizon mode

Sources of randomnessShip residual capacity for taking empty containers (given port and time period)Demand for containers at each port/timeSupply of containers at each port /time before unloading from ships


Formulation (2)

Minimize total expected (cost – revenue from demand)Ship container conservation: containers unloadedShip container conservation: containers loaded for repositioningPort container conservation / demand satisfactionShip residual capacity for repositioningNumber of leased containers


Plan

What are we talking about?Brief overview of freight transportationContainer-based intermodal transportationSystem design (location)Fleet Management (empties)Perspectives


Perspectives

Intermodal transportation Growing steadily & should continue to growContainers and other modes

Profound modifications to the economic, regulatory, technological, social and political environment of industryGlobalization, automation, ITS, e-logistics, security, …Need for innovative and enhanced planning and management proceduresOpportunities for Operations Research and Transportation Science


Perspectives (2)

A number of research efforts and important resultsMuch more work is needed!Many issues application areas not/little addressedIndustry evolution ⇒ New problemsPorts & terminals

Planning (all levels)Integration of operations & equipment typesAutomation


Perspectives (3)

Carrier strategic & tactical planningMore studied than terminals, but Better representation/integration of “local” operations and characteristicsIntegration of employee scheduling impacts/relationsBetter representation of time dependenciesBetter integration of stochastic aspects into long-term planning modelsAlgorithmic developments


Perspectives (4)

Short-term planningTime-dependent, stochastic formulations and algorithms Integrated models, e.g.,

Container fleet management over land and seaVehicles, power, crews, …

Modelling of ITS and e-logistics and integration to planning and management models; e.g.,

Flow of informationImpact on uncertainty


Perspectives (5)

Modelling the impact of security measures and addressing the new issuesLogistic networks

Coordination & synchronizationInformation flows and uncertainties

MethodologyModels Methods exact and (meta) heuristicParallel computation

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