Since the only available locomotives were tank engines with low tractive power, such as the Class PtL 2/2, passenger coaches of a particularly light design were required.

Between 1905 and 1911 a total of 281[1][2] wagons of classes BL, BCL, CL and PPostL were procured, all of which - except for the wagons of Class PPostL - had a uniform floor plan, open platforms at each end with Dixi gates on the steps and gangways only protected by a single iron railing.

Between 1906 and 1909, 74 of these wagons, built to the specifications of Design Sheet 570, were procured in a total of five batches from the company of Waggonfabrik Josef Rathgeber in Munich.

After the end of the Second World War in 1945, the location of other new coaches could no longer be ascertained.

The coaches had riveted half-timbered axle boxes of the short type, made of sheet steel.

Due to the long wheelbase of 5,000 millimetres, standard VDEV radial axles were used.

The coaches had folding branch line steps, which were later replaced by normal ones.