With its container scanning arm extended, the driver moves the truck slowly along a container as the terminal tug and trailer remain stationary. Once completed for the day, the articulated x-ray arm folds up and stows on top of the cabin. The scanner operator(s) occupy the cabin space immediately behind the cab, which is not connected to the cab.
1. Scanning arm deployed, the truck is ready to scan a container. The open door is access to the operator's cabin.
2. Scan in progress, the tuck moves slowly parallel to the container. The terminal tug driver has vacated his cab to avoid excessive gamma ray exposure.
4. Scanning completed for the day, the arm folds up.
5. Then the whole operating unit pivots in line with the chassis.
6. With the scanning unit safely nested in place, the rig is road ready. (I have never seen the drop axle in use).