Noroc! Hai sa va explic care sta treaba cu vagoanele de la KUEHN MODELL TT, va scriu in engleza ca nu prea mai vorbesc romaneste
The GDR-made 24.5 meters cars are following:
ОСЖД (OSZhD)-type B:
– made from 1962 to 1965
– variants: 1st, 2nd and mixed 1st and 2nd class coaches, 2nd class couchette coaches, sleepers, 3 cars of special versions
– delivered to GDR railroad, sleepers also to Bulgaria
– made from 1965 to 1969, sleepers and diners until the 1980's
– variants: 1st, 2nd and mixed 1st and 2nd class coaches, 2nd class couchette coaches, diners, sleepers, Soviet-style sleepers (exchangeable trucks for two gauges, ribbed sides, different window and compartment arrangements, some air-conditioned)
– delivered to Czechoslovakia (all versions, some regular sleepers equipped with exchangeable trucks for two gauges and Soviet-style EOT lights), GDR (no diners and no Soviet-style sleepers); sleepers also went to Poland (300 cars, all equipped with exchangeable trucks for two gauges and Soviet-style EOT lights), Hungary, Romania and Bulgaria; Soviet-style sleepers went (besides Czechoslovakia) to Soviet Union
standard-(fitting both ОСЖД [OSZhD] and UIC standards)-type Y/B70:
– made from 1969 to the 1980's
– variants: 1st, 2nd and mixed 1st and 2nd class coaches, 2nd class couchette coaches, combined 2nd class coaches with baggage compartment, baggage cars (and I'm not sure if also combined baggage cars with RPO compartment), customized and air-conditioned variants for non-European customers, special versions for government and military trains of various countries
– I don't have an overview which variants were delivered to which countries. Customers were: GDR, Czechoslovakia, Poland, Hungary, Romania, Bulgaria, Greece, Syria, Iraq and Iran.
Tillig makes all 3 types; Kühn makes only Y/B70 type.
Your reservations are legitimate concerning almost all East German compartment cars.
But there's an exception—the orange and ivory "Städte-Expreß" cars of the Y/B70 type.
Once upon a time, there were 110 new passenger cars—103 1st class coaches and 7 combined 2nd class coaches with baggage compartment. They were made in Bautzen to order of Czechoslovakian National Railroads (ČSD). But when the cars were finished, ČSD lacked the money to pay for them and cancelled the whole order.
Because they couldn't find another buyer and resources shouldn't be wasted, German Imperial Railroad (DR) bought the cars.
The cars were made according to Czechoslovakian specifications. So for instance, they were equipped with Czechoslovakian Dako brakes while DR otherwise used Knorr standard brakes.
The combines kept their green color and were quickly put in service in regular inter city trains (mainly international). They stayed DR's only combines with a length of 24.5 meters.
But what to do with so many 1st class coaches? So DR revived an old plan. Already in the early 1970's they had planned to instal a high-quality train network connecting Berlin with the other major cities of the GDR non-stop. The plan had been to obtain DMU's for this purpose—an improved version of VT18.16. Because of financial problems this plan had been postponed again and again. 103 coaches was the ideal size of a fleet which could be used to realize this old plan with locomotive hauled trains.
So these 103 coaches got recolored in a new orange and ivory livery. But actually DR intended to offer both 1st and 2nd class in these trains called "Städte-Expreß". How to alter a part of the cars into 2nd class coaches without spending lots of money? So they de-fined 60 of these 1st class cars. They simply removed the carpets and headrest pillows and used them in other 1st class cars. So the 2nd class coaches of the "Städte-Expreß" came to be.
These 60 cars were DR's only 2nd class coaches with 1st class seating. And it's not only about the seats, it's also about the length of the compartments. 2nd class coaches and couchette coaches of the 24.5 meters long types (types B, Y and Y/B70) had 10 compartments each while 1st class and mixed 1st and 2nd class coaches had 9. These 60 cars were DR's only 2nd class coaches of this size with only 9 compartments.
So these cars were exceptional. All cars obtained later for the "Städte-Expreß" network (the "long Halberstadt cars", 26.4 meters long) had regular interiors again.