Public transport plans are a planning tool which helps to assure the provision of adequate public transport infrastructure and services, economic operations as well as harmonized tariffs and timetables. They set the foundation for the work of transit alliances and other transport planning authorities. Read more here (German language only):
http://www.vrr.de/imperia/md/content
GIZ has published an overview of German public transport funding, along with two detailed case studies: one on tendering public transport services in Frankfurt and one on integrated transport operation in Berlin.
http://sustainabletransport.org/case-studies-on-funding-sustainable-public-transport