A vast number of Cid 21 passenger coaches came to the DB after the second world war. The DB couldn't do without this relatively new coach and put it into passenger services throughout Germany. When third class coaches were abolished in 1956, the Cid coaches were upgraded to second class and used from that time on with the designation Bid 21. Passengers paid for the comfort of the fourth class coach, which was abolished in 1928, with a new second class ticket.
