Railcars Btx761s, numbered 50 54 29-29, called Balm in the 60s and 70s, marked as Bix in the 80s and 90s and as 020 until 1. January 2009, are a series of four-axle second-class high-capacity passenger coaches of the Czech Railways park. All these cars were manufactured for the Czechoslovak State Railways in 1958–1969 in the factory Vagonka Studenka. The cars were to be designed as a trailer to motor railcars 820, but used with other DMU (830, 850, 842 etc)