Final answer:
The marshalling restriction pertaining to loaded multi-level autos is to limit to 15 cars per track, which ensures safety and efficient handling.
Step-by-step explanation:
In the context of rail transport, marshalling refers to the practice of organizing and assembling rail cars according to a specific set of guidelines or restrictions. When dealing with loaded multi-level autos, marshalling restrictions are important for safety and logistical reasons. Specifically, one such restriction pertaining to the marshalling of loaded multi-level autos is to limit to 15 cars per track. This restriction is in place to ensure safe and efficient handling and movement of the rail cars, as too many cars on a track could lead to issues such as increased braking distances or the risk of derailment.