Each of the seven major railroads in North America (called the Class I railroads) own between 20,000 and 50,000 miles of track and run about 2,000 trains per day. The railroads handle a range of traffic that includes intermodal, automobile transport, manifest freight, and passenger, all with unique priorities and scheduling requirements. Typically, rail operations are managed by geographic area from centralized dispatch centers. Each dispatcher in a dispatch center controls a section of the track and manually plans all activities associated with moving trains over that section. Norfolk Southern and GE competed in the 2017 Franz Edelman Award Competition.
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Manual dispatching of trains leads to suboptimal operations. A dispatcher focuses only on a small track section and does not have a global view of the entire rail network. Therefore, what looks locally optimal may harm the network. Moreover, the complexity of the system makes it difficult to make even locally optimal decisions. As a result, trains end up waiting for long periods of time at meet-and-pass locations, and require activities such as crew changes to be performed at expensive locations. Currently, freight trains in North America travel at an average speed of around 20 miles per hour. Increasing this speed by one mile per hour saves a typical Class I railroad over $200 million per year.
The optimal dispatching of trains requires quick and efficient generation of movement plans in real time. A movement plan is a detailed plan for dispatching trains on a rail network. It is also called a meet-pass plan as it involves planning meet locations where trains traveling in opposite directions can get past each other, and determining pass locations where a fast train can overtake a slower train traveling in the same direction. Generating a movement plan is a complex optimization problem requiring many decisions including the path that each train needs to take from origin to destination, the meet and pass locations in the planning horizon, the locations for crew changes, etc. Generating even a good feasible solution for real-world problems using existing techniques is very difficult. Many attempts that were made earlier to solve this problem met with limited success, and there is no evidence of any other successful implementation of movement planner at any railroad.
General Electric (GE) partnered with Norfolk Southern (NS) Railway to develop and implement a novel algorithm that exploits the problem structure to systematically search the feasible space to generate a robust plan in real time. It employs a hybrid combination of heuristic methods, local optimization techniques, and backtracking methods to develop a near-optimal plan that significantly improves a railroad’s performance metrics. NS railroad currently uses this algorithm to dispatch trains over its 11 divisions comprising 20,000 miles of track resulting in a 2 mph increase in average speed, and saving NS over $400 million per year. The capacity of the rail network improved without laying additional track and crew expirations have decreased by 60 percent. On average, freight trains now arrive at their destinations eight minutes early. Prior to the implementation of the algorithm, they were 100 minutes late on average.
GE is implementing this algorithm at two other railroad companies and is in talks to deploy it at several other railroads in the U.S. and abroad. To date, revenues to GE from this product are well over $100 million. The success of the movement planner algorithm led to a major growth in the optimization-based solutions business of GE. GE Transportation now offers a connected suite of solutions to the railroad industry under the brand name RailConnect 360 to minimize fuel consumption, increase network throughput, improve productivity, and maximize asset utilization.
General Electric
General Electric (GE) is building the world by providing capital, expertise, and infrastructure for a global economy. GE Capital has provided billions in financing so businesses can build and grow their operations and consumers can build their financial futures. The appliances, lighting, power systems and other products built by GE help millions of homes, offices, factories, and retail facilities around the world work better.
Norfolk Southern Corporation
Norfolk Southern (NS) Corporation is one of the nation’s premier transportation companies. Its Norfolk Southern Railway Company subsidiary operates approximately 19,500 route miles in 22 states and the District of Columbia, serves every major container port in the eastern United States, and provides efficient connections to other rail carriers. Norfolk Southern operates the most extensive intermodal network in the East and is a major transporter of coal, automotive, and industrial products.