OR Modeling in Intermodal:

Intermodal Railcar Management

Dharma Acharya, Jagadish Jampani, Aihong Wen

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Why IRM?

• Currently Repositioning of Intermodal Flat Cars is Done Manually

• Difficult for a Human Being to Consider all the Options Available and Quantify Consequences of his/her Decision– Invisibility into the System/Inventory– Equipment Shortages and Surpluses– Unnecessary Empty Moves and Car Hire Costs– Loads Left on Ground (LOG)– Customer Satisfaction

IRM Optimization

Cost Parameters

Supply

DemandForecast

Terminals

Interchanges

Trains

Car Reposition Instructions

Terminal Surplus/Shortage

Objective: Optimize the Repositioning of Intermodal Flat Cars

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Demand Forecast

• Forecast Trailer/Container Volume Flat Car Length

• Forecast at OD Pair, Trailer/Container Type and Day of Week Level

• Use Advanced Time Series Modeling to Generate Seed Forecast

• Terminal Managers can Review the Seed Forecast and Override if Necessary

• Challenges in Identifying Data Sources and the Granularity of the Forecast to Meet the Optimizer Need

• Forecast Horizon ~ 5 days

Other Model Inputs

• Supply– Intermodal Terminal– Serving Yard– En-route on Train– Billed but at Other Yards– Predicted Interchange

• Trains– Train Profile– Train Routes– Blocking Plan– Used Capacity on En-route Trains

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Other Model Inputs (contd.)

• Terminal– Associated Serving Yards– Operating Days– Cars Unloading Time– Staging Time– Max Cars Holding Capacity

• Interchange Profile

• Cost Parameters– Car Hire Costs– Penalty Costs

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Model Constraints

• Supply and Demand Constraints by Equipment Type• Train Specific Maximum Length Capacity• Constraints Related to Train Profile

– Days of Operation– Route of Trains– Block to Train Assignment

• Constraints Related to Intermodal Terminals– Capacity Restrictions– Days of Operation– Equipment Handling Capabilities

• Restrictions on Sending Certain Types of Cars only on Certain Lanes

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Model Objective and Output

• Objective – Minimize empty flatcar repositioning and car hire costs.

• Output– Empty Flatcars Reposition Instructions

• Cars Origin and Destination• Potential Trains to Move the Cars• Associated Departure and Arrival Times

– Terminal Surpluses/Shortages • Equipment Type• By day

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