Serial letters with an international value as of January 1st, 2015:
- A: 1st class coach with seats;
- B: 2nd class coach with seats;
- AB: 1st / 2nd class coach with seats;
- WL: sleeping-car with serial letter A, B or AB depending on the type of accommodation offered. The serial letters for sleeping-car with “special” compartments are supplemented with index-letter “S”;
- WR: dining-car;
- R: coach with dining-car, buffet or bar compartment (serial-letter used in addition);
- D: van;
- DD: open, 2-tier car-carrier van;
- Post: mail van;
- AS / SR / WG: bar coach with dancing facilities;
- WSP: Pullman coach;
- Le: open 2-axle 2-tier car-carrier wagon;
- Leq: open 2-axle 2-tier car-carrier wagon fitted with train supply cable;
- Laeq: open 3-axle 2-tier car-carrier wagon fitted with train supply cable.

Index letters with an international value as of January 1st, 2015:
- b / h: coach fitted out to carry disabled passengers;
- c: compartments convertible into couchette accommodation;
- d / v: vehicle fitted to receive bicycles;
- ee / z: vehicle fitted with central power supply;
- f: vehicle fitted with driver’s cab (driving trailer);
- p / t: centre-aisle coach with seats;
- m: vehicle over 24,5 m in length;
- s: centre-aisle in vans and coaches with luggage compartment.