Interoperability codes used for freight wagons as of January 1st, 2015:
- 01: freight wagons with axles and fixed track gauge;
- 02: freight wagons with axles and variable track gauge;
- 09: PPV/PPW freight wagons with axles and variable track gauge;
- 11: freight wagons with bogies and fixed track gauge;
- 12: freight wagons with bogies and variable track gauge;
- 19: PPV/PPW freight wagons with bogies and variable track gauge;
- 21 / 23 / 25 / 27: freight wagons with axles and fixed track gauge;
- 22 / 24 / 26 / 28: freight wagons with axles and variable track gauge;
- 29: PPV/PPW freight wagons with axles and fixed track gauge;
- 31 / 33 / 35 / 37: freight wagons with bogies and fixed track gauge;
- 32 / 34 / 36 / 38: freight wagons with bogies and variable track gauge;
- 39: PPV/PPW freight wagons with bogies and fixed track gauge;
- 40: maintenance related wagons with axles and fixed or variable track gauge;
- 41 / 43 / 45 / 47: other wagons with axles and fixed track gauge;
- 42 / 44 / 46 / 48: other wagons with axles and variable track gauge;
- 49: wagons with axles and with special numbering for technical characteristics not placed in service inside EU or a COTIF Contracting State;
- 80: maintenance related wagons with bogies and fixed or variable track gauge;
- 81 / 83 / 85 / 87: other wagons with bogies and fixed track gauge;
- 82 / 84 / 86 / 88: other wagons with bogies and variable track gauge;
- 89: wagons with bogies and with special numbering for technical characteristics not placed in service inside EU or a COTIF Contracting State.