Academic solutions to railroad problems - Rail Update

Railway Age, April, 2003

The INFORMS/RASIG (Institute for Operations Research and Management Science/Rail Special Interest Group) has announced the winners of its 2002 Student Paper contest, which was co-sponsored by Railway Age. Following are abstracts of the winning papers, which were presented at the INFORMS San Jose conference.

Tied for first place:

* Solving Real-Life Locomotive Scheduling Problems, by Jian Liu, University of Florida, Gainesville, Fla. "The problem is how to assign locomotives with sufficient power to trains on a pre-planned schedule. Our solution divides the problem into smaller pieces that can be efficiently solved. Comparing our solution with that of in-house software developed by CSXT showed that we obtained a savings of over 400 locomotives. However, our model presumes a scheduled railroad, so a scheduled operation would be a necessary precondition."

* Shunting Passenger Train Units in a Railway Station, by Ramon M. Lentink, Dennis Huisman, Leo G. Kroon, and Richard Freling, Erasmus University, Rotterdam, Netherlands. "Shunting occurs whenever cars or trains are temporarily not needed to meet demand, as in off-peak periods. Given limitations of space and the arrangement of yard tracks, the problem is how to stow excess passenger train units in a sequence that facilitates convenient reassembly later. We present computational results based on real life instances from Netherlands Railways."

Second place:

* Ant Colony Systems Applied to Switch Engine Assignment and Routing in a Railroad Yard, by Jodelson Sabino, Federal University of Espirito Santo, Vitoria ES, Brazil. "We explore the application of a multiple colony ant systems metaheuristic model, called COMPETants, for railroad yard operations improvement. Given a track layout, available shunting locomotives of different sizes, and a list of switch orders to be executed, we aim to find the best way to assign switch orders to the engines to minimize the total cost of yard operations. We want to minimize light running, waiting times, and the number of switch engines working in each shift. All the switch orders have to be accomplished in the right sequence, within the allowable time frame."

In addition to its Student Paper Contest, RASIG sponsors an annual roundtable session, as well as technical paper tracks that focus on current industry issues. The San Jose roundtable was "Railroads in their Customers' Supply Chains." It featured presentations from CN, BNSF, CP/Tronicus, August Designs, and NS Modalgistics. Additional technical sessions focused on freight car routing and scheduling, interchange gateway optimization, planning truck drayage operations, empty equipment distribution, service design, and line capacity modeling.

What is operations research? Bruce W. Patty of Exostrategy Partners, Sausalito, Calif., describes it as "a structured, analytical approach to making decisions involving the best use of scarce resources."

"Most people who are involved with railroads aren't aware of what is going on behind the scenes of decisions that are made operationally, tactically, and strategically," says Patty. "Decision support systems, computer-based systems with OR models inside, have been and are being used to make decisions every day. In fact, railroads have made use of OR models since the early 1980s, with some of the earlier systems now being improved with second-generation tools."

For example, at Norfolk Southern, decisions are made continuously regarding the assignment of locomotives to trains. Several factors go into these decisions: horsepower requirements, maintenance schedules, repositioning needs, locomotive assignment preferences, and current status. Decisions have historically been made manually, but with experienced dispatchers approaching retirement age, a more efficient approach was needed. To help make these decisions, a Locomotive Planning System was developed by NS in collaboration with operations researchers from Princeton University's CASTLE Laboratory. The NS model is being adapted for use at BNSF.

RASIG has over 100 railroad employees, consultants and academic members. The next annual meeting is planned for October 19-21, 2003 in Atlanta, Ga. For more information, or to retrieve information on past RASIG meetings, see RASIG's website, http://railroadappl.section.informs.org. Railway Age will again be co-sponsoring the Student Paper Contest.