Together with the University of Gdansk and the Trolleybus Company in Gdynia (PKT) the TROLLEY partner City of Gdynia has published a comprehensive handbook for the conversion of diesel engine buses into trolleybuses.
http://regional-cooperation.eu/new-trolley-publication-handbook-diesel-bus-conversion http://pipes.yahoo.com/pipes/pipe.info?_id=5d82ddc85603e45bd143a7e19c42ecb5