In continuation of an old Reichsbahn tradition, Deutsche Bahn's passenger cars are designated by an alphabetic type code. This consists of a leading class code (capital letters) and a varying number of additional lower-case letters which are technically flags -- the presence of one such letter indicates some specific property of the car; if a lower-case letter is absent, the respective feature isn't present either.

Class codes

(A D prefixed to a non-D class code indicates a double-decker car; some codes can be combined, thus WLA is a first-class-only sleeping car.)

• A -- first-class-only car
• AB -- mixed first-class/second-class car
• AR -- first-class-only car with pantry and dining room
• B -- second-class-only car
• BD -- second-class-only car with luggage compartment
• BR -- second-class-only car with pantry and dining room
• BS -- second-class-only car with special installations
• D -- luggage car
• DD -- open double-decked auto transporter (for AutoZug)
• K -- narrow-gauge car
• MD -- luggage car (irregular construction) or auto transporter
• Post -- mail car
• WG -- entertainment car
• WL -- sleeping car
• WS -- dining car / service car

Affixed flags

Flags in their regular order of appearance:

• p -- air-conditioned car with aisle and open seating
• v -- prefixed to an "m": indicates long-distance cars with less than a certain number of compartments; the number is 10 first-class compartments for A cars, 5 first-class compartments for AB cars, 12 second-class compartments for B cars and 6 compartments for BD cars
• o -- prefixed to an "m": same as "v", but without air conditioning
• i -- prefixed to an "m": InterRegio car (outdated, as the regular InterRegio network has been discontinued in favor of InterRegio Express and InterCity trains)
• n -- short-distance (local/commuter) car, longer than 24.5 m, with middle-aisle open seating in the second class equivalent to 12 compartments, an aisle in the first-class space, two middle doors per side and push-pull train capability
• y -- same as "n", but second-class space equivalent to 11 compartments and no special first-class features
• w -- light four-axled cars 18.7 m in length
• x -- S-Bahn push-pull-train car, at least 24.5 m in length, open seating with middle aisle in both classes, middle doors, 1000 V power supply from the locomotive and KE-GPR+ep high-performance brakes
• m -- long-distance car longer than 24.5 m, with 10 compartments if A, 12 compartments if B, six compartments if BD or five second-class compartments if AB (unless prefixed with "o" or "v")
• r -- on Post cars or if an "n" is present: indicates KE-GPR high-performance brakes
• s -- on luggage cars or cars with luggage compartments: indicates the aisle is on the side; on sleeping cars: indicates "Spezial" configuration
• b -- with special installations for handicapped persons in wheelchairs
• d -- if an "i" or "m" is present: indicates space for bicycle transport
• k -- with self-service restaurant/bistro or pantry compartment
• h -- cars with electrical installations that can be supplied either by the 1000 V cable from the locomotive or by running-wheel generators / old Deutsche Reichsbahn commuter cars with middle aisle
• u -- push-pull-train capability (34-pole control cable)
• z -- central power supply by 1000 V cable from the locomotive
• q -- non-modernised pre-1991 cab car (34-pole control cable)
• f -- cab car (36-pole control cable or better)

Exceptions to this order: with AR or BR cars the "k" always goes directly after the class code, as in ARkimbz or BRkimbz; so does the "s" for "Spezial" sleeping cars, as in WLABsm.

Other flags:

• g -- large-profile car
• uu -- DB Regio luggage car for bicycle transport