The availability of public transport data (bus/train stop/station gis data) including shedules/frequencies in a standardised format such as naptan or gtfs would allow for the development of routing applications and optimisation research. Currently, the data is closed and seems only to be disclosed to organisations or projects receiving significant funding from the EU for public transport information services.

http://govfresh.com/2010/08/the-case-for-open-transit-data/