Abstract: A method and system for operating a pipeline conveying two dissimilar materials that gathers data about material flowing in the pipeline, identifies a first line and determines a slope of the first line of a first subset of the gathered data, and if an absolute value of the slope of the first line equals or exceeds a first threshold value, then sends a message indicating that transmix has been detected; identifies a second line and determines a slope of the second line of a second subset of the gathered data, and if an absolute value of the slope of the second line equals or is less than a second threshold value, then sends a message indicating that transmix has ended. A position of at least one valve is modified in response to the message that transmix has ended.