A tunnel may have a housing with an entrance, an exit, and a pathway extending from the entrance to the exit through the housing. The tunnel may be used for performing operations, such as cleaning operations within the tunnel. A conveyor may be configured to move articles through the housing along the pathway. One or more detectors may be configured at discrete locations along the pathway. One or more curtains may be configured between the entrance and the exit of the housing to partition the pathway into two or more segments. One or more sensors may be configured in each curtain. The one or more sensors may be detectable by the one or more detectors to determine the presence, position, orientation, or other characteristic of each curtain.