Because of increasing traffic in urban areas, public transport has to become more attractive and efficient by introducing computer-aided dynamic passenger information and on-line vehicle location. The tram location pilot system described makes vehicle scheduling and control systems independent of expensive location infrastructure (e.g. beacons). It uses on-board autonomous DGPS positioning with dead reckoning and a radio link to the control centre. The evaluation of the measured vehicle positions clearly demonstrates that operational accuracy requirements for public transport applications are met. The whole Tramway Location System (TLS) is structured into the 3 segments: on-board equipment, components of the operation centre and roadside equipment. The trial set-up for dynamic real-time measurements of the positioning accuracy is described, and the results of the evaluation of more than 7300 position fixes at 15 geodetically measured reference points along the tramway are presented. The conclusions indicate that, during runs in city environments, DGPS combined with dead reckoning achieves vehicle positioning precise enough to enable a reliable, improved and up-to-date passenger information service at the stops.