Deprecated. Please download from vbb-gtfs.jannisr.de.
This is was open GTFS data for the Berlin Brandenburg public transport service (VBB), published as CC BY 3.0 on the Berlin Open Data website.
I do not own this data, it is owned by VBB Verkehrsverbund Berlin-Brandenburg GmbH. VBB claims it is valid from end of August to December 2016, although they often break this promise.
