The PwPost Bay 06 was a combined mail and luggage van designed for Lokalbahn branch line train services with the Royal Bavarian State Railways in the early 20th century. It was built to their Design Sheet Number 606.

As Bavaria's network of Lokalbahn railways grew so did the requirement for suitable coaches for local passenger transport. Because the only motive power available were tank locomotives with low tractive power, such as the PtL 2/2, coaches of a special lightweight construction were needed.

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. Large window panes were fitted instead of the composite windows that had been usual up to that point. They are sometimes referred to as 'the shorts' or 'the short ones' (Die Kurze).

Because the construction of individual mail or luggage vans on the lightly used Lokalbahn routes was too expensive and unnecessary, between 1905 and 1911 87 combined mail/luggage vans were procured, of which 79 were of the type PwPost Bay 06 built to Design Sheet 606. They were delivered in eight batches by the firms of MAN and Rathgeber. Of these vans, three were transferred in 1908 and 1911 to the former Palatine Railways, where they were registered under Sheet Nos. 221 and 223.^[3]

Of the original 79 vans, by 1940 five had been retired. A total of 44 were taken over by the DB, who retired them by 1963. As early as 1932 eight vans were converted into PwL Bay 06/32 by the removal of the mail compartment; another nine vans were converted in the years after 1945.

The following coaches were also built for the Lokalbahn branch line network:

• BCL Bay 09, long passenger coach
• CL Bay 06b, short passenger coach
• GwL, goods van
• CL Bay 11a, long passenger coach