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Subway Environment Simulation (SES) Computer Program

The SES program analyzes tunnel environments. It is a one-dimensional airflow and thermodynamic solver. Previously, the distribution of the program was limited. After removing restrictions by the United States Government, Never Gray distributes the original 4.1 version of the program. Never Gray also provides free and paid software to aid with analyses.

SES 4.1 Download

Download the Zip file, unzip the contents, and run "setup.exe". To use the original Input Manager and SES batch manager in Windows 10 (32- and 64-bit) you'll need to "Run compatibility troubleshooter" by selecting Properties>Compatibility on the executables (sesin.exe and SESBatch.exe). Alternatively, try Next-In, a free Excel-based input manager.

File Size: 9.0 MB

MD5: 6682b62ea2ef023ecdc93fd26cbeaf67

SHA256: f438f5ac5c050bdfc7bcc85e566e40eec25853e60eec8d3da5ef4f7f10bfb9f6

Pre and Post Processing  Tools

Process Diagram.png

Free Input Manager


Next-In gives SES users the power to create and modify input files with Excel.


Next-Vis GUI 1p10.png

SES text output is converted to Excel files and Visio flow diagrams


Never Gray is participating in an open-source fork of the existing 4.1 version of SES, called OpenSES. Subscribe to the Next SES Newsletter at the bottom of the page to get the latest news. Check out the latest development efforts at

SES Training

Learn more about SES training offered by Never Gray. 

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