Modern navigation systems use multi-sensor-systems for location determination in combination with GPS or DGPS. Limitations in the availability of satellites due to shadowing and multi path effects in urban areas, magnetic disturbances, wheel slips and error propagation of dead reckoning lead to loss of position information. This can be avoided by map matching which compensates for typical sensor errors. This contribution deals with methods and procedures of map matching, aiming to develop a robust procedure for autarkic rail vehicle localization. Special requirements for railway traffic have to be fulfilled: - High availability and reliability of the positioning information, precise track positioning - Support of GPS measurements in case of multi-path effects or difficult reception conditions - Use of low-cost sensors