Abstract: A tray packing-shrink wrapping machine for packaging articles along a conveyor is disclosed. The machine is operable in a dual lane mode and a single lane mode. In both modes a collation section receives articles from an infeed section and arranges the articles into rows and columns to create batches of articles. In dual lane mode a lane divider structure separates each batch into smaller microbatches. Separate trays and sheets of heat shrinkable film are simultaneously formed around the microbatches. An in-line stacker is selectively operable in single lane or dual lane modes to stack a packed tray on top of the preceding packed tray. The machine is quickly converted to single lane mode by removing the lane divider structure and center trayforming structures, removing the center stacker elements and retracting knives in the blank feeding and film wrapping devices. A method for converting a dual lane machine to a single lane machine is also disclosed.