Category and index letters for articulated and multiple freight wagons as of January 1st, 2015:

Index letters with an international value common to all categories:
- q: pipe for electric heating which can be supplied by all accepted currents;
- qq: pipe and installation for electric heating which can be supplied by all accepted currents;
- s: wagons authorised to run under "s" conditions (max. speed 100 km/h);
- ss: wagons authorised to run under "ss" conditions (max. speed 120 km/h).

Index letters with a national value:
t, u, v, w, x, y, z

F: open high-sided wagon (reference wagon: articulated or multiple wagon with axles, with 2 units, inside length of the wagons between 22 m and 27 m):
- a: with bogies;
- c: with controlled gravity unloading, on both sides, alternately, at the top (without a flat floor and have no tipping facility either at the end or the side);
- cc: with controlled gravity unloading, on both sides, alternately, at the bottom (without a flat floor and have no tipping facility either at the end or the side);
- e: with 3 units;
- ee: with 4 units or more;
- f: suitable for traffic with Great Britain;
- ff: suitable for traffic with Great Britain (by tunnel exclusively);
- fff: suitable for traffic with Great Britain (by train-ferry exclusively);
- l: with bulk gravity unloading, on both sides, simultaneously, at the top (without a flat floor and have no tipping facility either at the end or the side);
- ll: with bulk gravity unloading, on both sides, simultaneously, at the bottom (without a flat floor and have no tipping facility either at the end or the side);
- m: with 2 units inside length of the wagons over 27 m;
- mm: with 2 units inside length of the wagons under 22 m;
- o: with axial bulk gravity unloading, at the top (without a flat floor and have no tipping facility either at the end or the side);
- oo: with axial bulk gravity unloading, at the bottom (without a flat floor and have no tipping facility either at the end or the side);
- p: with axial controlled gravity unloading, at the top (without a flat floor and have no tipping facility either at the end or the side);
- pp: with axial controlled gravity unloading, at the bottom (without a flat floor and have no tipping facility either at the end or the side);
- r: articulated wagon;
- rr: multiple wagon.

H: covered wagon (reference wagon: articulated or multiple wagon with axles, with 2 units, inside length of the wagons between 22 m and 27 m):
- a: with bogies;
- c: with end doors;
- cc: with end doors and fitted internally for the transport of motor cars;
- d: with floor traps;
- e: with 3 units;
- ee: with 4 units or more;
- f: suitable for traffic with Great Britain*;
- ff: suitable for traffic with Great Britain (by tunnel exclusively);
- fff: suitable for traffic with Great Britain (by train-ferry exclusively)*;
- g: for grain;
- h: for fruits and vegetables (applies only to wagons provided with additional ventilation apertures at the floor level);
- i: with opening or shunt walls;
- ii: with very robust opening or shunt walls (only applicable to 1435 mm gauge wagons);
- l: with movable partitions (movable partitions may be dismounted temporarily);
- ll: with lockable movable partitions (movable partitions may be dismounted temporarily);
- m: with 2 units, length of the wagons over 27 m;
- mm: with 2 units, length of the wagons under 22 m;
- r: articulated wagon;
- rr: multiple wagon.

I: temperature-controlled wagon (reference wagon: refrigerator wagon, with class IN thermal insulation, with motor-driven ventilation, with gratings and ice bunker over 3,5 m³, articulated or multiple wagon with axles, with 2 units, inside length of the wagons between 22 m and 27 m):
- a: with bogies;
- c: with meat hooks;
- d: for fish;
- e: with electric ventilation;
- ee: with 4 units or more;
- f: suitable for traffic with Great Britain;
- ff: suitable for traffic with Great Britain (by tunnel exclusively);
- fff: suitable for traffic with Great Britain (by train-ferry exclusively);
- g: with mechanical refrigeration;
- gg: refrigerator with liquefied gas;
- h: with class IR thermal insulation;
- i: mechanically refrigerated by the machinery of an accompanying technical wagon;
- ii: accompanying technical wagon;
- l: insulated without ice bunkers;
- m: with 2 units, length of the wagons over 27 m;
- mm: with 2 units, length of the wagons under 22 m;
- o: with ice bunkers of capacity less than 3,5 m³;
- oo: with 3 units;
- p: without gratings;
- r: articulated wagon;
- rr: multiple wagon.

L: flat wagon with separate axles (reference wagon: articulated or multiple wagon, with 2 units, inside length of the wagons between 22 m and 27 m):
- a: articulated wagon;
- aa: multiple wagon;
- b: with special fittings for securing purposes for medium-sized containers;
- c: with swivelling bolster;
- d: fitted out for the transport of motor cars, without deck;
- e: with decks for the transport of motor cars;
- f: suitable for traffic with Great Britain;
- ff: suitable for traffic with Great Britain (by tunnel exclusively);
- fff: suitable for traffic with Great Britain (by train-ferry exclusively);
- g: fitted for the transport of containers (wagons used solely for the transport of containers);
- h: fitted out for the transport of steel coils, eye to side (wagons used solely for the transport of steel coils);
- hh: fitted out for the transport of steel coils, eye to sky (wagons used solely for the transport of steel coils);
- i: with removable cover and non-removable ends;
- ii: with very robust removable metallic cover (only applicable to 1435 mm gauge wagons) and non-removable ends;
- j: with shock-absorbing device;
- l: without stanchions;
- m: with 2 units, inside length of the wagon between 18 m and 22 m;
- mm: with 2 units, inside length of the wagon under 18 m;
- o: with 3 units;
- oo: with 4 units or more;
- p: without sides;
- r: with 2 units, inside length of the wagon over 27 m;

S: flat bogie wagon (reference wagon: articulated or multiple wagon, with 2 units, inside length of the wagons between 22 m and 27 m):
- b: with special fittings for securing purposes for medium-sized containers;
- c: with swivelling bolster;
- d: fitted out for the transport of motor cars, without deck;
- e: with decks for the transport of motor cars;
- f: suitable for traffic with Great Britain;
- ff: suitable for traffic with Great Britain (by tunnel exclusively);
- fff: suitable for traffic with Great Britain (by train-ferry exclusively);
- g: fitted for the transport of containers, total loading length up to 60 feet;
- gg: fitted for the transport of containers, total loading length over 60 feet;
- h fitted out for the transport of steel coils, eye to side;
- hh fitted out for the transport of steel coils, eye to sky;
- i: with removable cover and non-removable ends;
- ii: with very robust removable metallic cover (only applicable to 1435 mm gauge wagons) and non-removable ends;
- j: with shock-absorbing device;
- l: without stanchions;
- m: with 2 units, inside length of the wagon over 27 m;
- mm: with 2 units, inside length of the wagon under 22 m;
- o: with 3 units;
- oo: with 4 units or more;
- p: without sides;
- r: articulated wagon;
- rr: multiple wagon.

T: wagon with opening roof (reference wagon: articulated or multiple wagon, with 2 units, inside length of the wagons between 22 m and 27 m):
- a: with bogies;
- b: with unobstructed height of doors over 1,90 m;
- c: with end doors;
- d: with controlled gravity unloading, on both sides, alternately, at the top;
- dd: with controlled gravity unloading, on both sides, alternately, at the bottom;
- e: with 3 units;
- ee: with 4 units or more;
- f: suitable for traffic with Great Britain;
- ff: suitable for traffic with Great Britain (by tunnel exclusively);
- fff: suitable for traffic with Great Britain (by train-ferry exclusively);
- g: for grain;
- h fitted out for the transport of steel coils, eye to side;
- hh fitted out for the transport of steel coils, eye to sky;
- i: with opening walls;
- j: with shock-absorbing device;
- l: with bulk gravity unloading, on both sides, simultaneously, at the top;
- ll: with bulk gravity unloading, on both sides, simultaneously, at the bottom;
- m: with 2 units, inside length of the wagon over 27 m;
- mm: with 2 units, inside length of the wagon under 22 m;
- o: with axial bulk gravity unloading, at the top;
- oo: with axial bulk gravity unloading, at the bottom;
- p: with axial controlled gravity unloading, at the top;
- pp: with axial controlled gravity unloading, at the bottom.
- r: articulated wagon;
- rr: multiple wagon.

U: special wagons (reference wagon: articulated or multiple wagon, with 2 units, inside length of the wagons between 22 m and 27 m):
- a: with bogies;
- c: with unloading under pressure;
- d: with controlled gravity unloading, on both sides, alternately, at the top;
- dd: with controlled gravity unloading, on both sides, alternately, at the bottom;
- e: with 3 units;
- ee: with 4 units or more;
- f: suitable for traffic with Great Britain;
- ff: suitable for traffic with Great Britain (by tunnel exclusively);
- fff: suitable for traffic with Great Britain (by train-ferry exclusively);
- g: for grain;
- i: fitted out for the transport of objects which should exceed the gauge if they were loaded on ordinary wagons;
- l: with bulk gravity unloading, on both sides, simultaneously, at the top;
- ll: with bulk gravity unloading, on both sides, simultaneously, at the bottom;
- m: with 2 units, inside length of the wagon over 27 m;
- mm: with 2 units, inside length of the wagon under 22 m;
- o: with axial bulk gravity unloading, at the top;
- oo: with axial bulk gravity unloading, at the bottom;
- p: with axial controlled gravity unloading, at the top;
- pp: with axial controlled gravity unloading, at the bottom;
- r: articulated wagon;
- rr: multiple wagon.

Z: tank wagon (reference wagon: with metal shell, for the transport of liquids or gases, articulated or multiple wagon, with 2 units, inside length of the wagons between 22 m and 27 m):
- a: with bogies;
- c: with unloading under pressure;
- e: fitted with heating devices;
- f: suitable for traffic with Great Britain;
- ff: suitable for traffic with Great Britain (by tunnel exclusively);
- fff: suitable for traffic with Great Britain (by train-ferry exclusively);
- g: for the transport of gases under pressure, liquefied or dissolved under pressure;
- i: tank of non-metallic material;
- j: with shock-absorbing device;
- m: with 2 units, inside length of the wagon over 27 m;
- mm: with 2 units, inside length of the wagon under 22 m;
- o: with axial bulk gravity unloading, at the top;
- oo: with axial bulk gravity unloading, at the bottom;
- r: articulated wagon;
- rr: multiple wagon.