Creating an Integrated Hump Yard Simulation System

CSX Transportation


Accuracy in simulation modeled


Received Chairman's Award for Excellence



As volumes continued to grow in CSX Transportation’s rail network, its hump yards became congested. Partnering with CSX, we developed an integrated hump yard simulation system to help the company determine a hump yard’s true capacity. We identified bottlenecks, recommended optimal capacity expansion options and identified yard improvement opportunities.


Business Problem

Hump yards are the nerve centers of a railroad the same way airport hubs are for airlines. As the volume on a railroad’s network grows, these yards needed to process more cars, and yard capacity became the bottleneck. Railroad planners needed specialized tools to determine a hump yard’s true capacity, identify bottlenecks and determine cost-effective methods to increase yard capacity. They also wanted to assess the impact of new technology on a yard’s capacity and efficiency. While railroad planners have traditionally used experience to answer these questions, executives at CSX Transportation decided to apply science to supplement insight and intuition. They hired Optym to develop an integrated hump yard simulation system to model multiple hump yards and create a platform to perform a variety of what-if studies.

Our Approach

After spending months at several hump yards understanding and documenting CSX’s operations, we modeled multiple hump yards in a single system, using core modules that applied to all yards. In our model, we created individual modules for each yard to capture CSX’s distinctive methods of operation. Ultimately, we developed a simulation system with more than 30 decision modules, over 100 operational parameters, eight manpower resources and 12 cost components. The outcome of this project was YardSYM®, a web-based decision support system that models all yard operations to a high level of accuracy, shows the animation of train movements in a yard and displays simulation results through a variety of reports, charts and graphs. The resulting simulation modeled most KPIs to within three percent of real-world numbers.

Key Benefits

  1. When CSX used YardSYM® to select the best sizing options for improving productivity in a hump yard, our options enabled it to reduce the cost per car processed by as much as six percent.
  2. CSX used YardSYM® to evaluate whether adding departure tracks in a yard would improve yard productivity and concluded that no justifiable return on investment would result. Consequently, YardSYM® yielded millions of dollars in savings on capital investments that were planned but not done as a result of this study.


CSX utilized YardSYM® for a variety of purposes, including analyzing infrastructure and automation changes, tactical and strategic decision making, capacity and service level assessments and yard stress tests. Thanks to YardSYM®, the CSX team involved in this project received the Chairman’s Award for Excellence in 2012.