In combined transport, the higher sections of most ITUs (Intermodal Transport Units) foul the loading gauge in various European countries when the units are loaded on wagons or bogies. Their carriage must therefore be covered by the procedure for exceptional consignments as per UIC Leaflet 502 (International Union of Railways).
In order to facilitate and speed up transport in a reliable manner, a coding system for various elements of combined transport was established. The system ensures safe operation of ITUs, indicates their loading gauges and ensures the owner is identified. UIC Leaflet 596-6 sets out the prescriptions for this system regarding ITUs, carrier wagons and lines. The system, which ensures safe operations, has been applied for several decades by various companies in the combined transport chain. Those who do not wish to apply the UIC 596-6 procedure have to take organisational measures which ensure the same level of reliability.