Due to the growing global popula­tion, increasing urbanisation and increasing fuel prices, passenger transport (in German, Öffentlicher Personennahverkehr, ÖPNV) is set to expand significantly in the coming years. The World Association of Pub­lic Transport UITP believes that pub­lic transport provision will double by 2025. Operators of public transport systems are therefore faced with the challenge of dealing with the in­creasing passenger numbers both as a result of the expansion and as a result of the modernisation of ex­isting systems. The decisions here focus on the highest safety stand­ards, maximum availability and a low life-cycle cost. A clear technological revolution from track circuits to wheel detection and axle counting systems can be seen in rail-based public transport systems. New lines and projects are already often equipped with modern axle counting systems, as the benefits of these far outweigh their functionality and operating costs. The requirements and the framework conditions in rail-based public trans­port systems do, however, differ sig­nificantly from those in the standard-gauge railway and long distance rail sectors. This article deals with the specific features in public transport systems and the ensuing demands on wheel detection and axle counting systems. It indicates that due to the very wide-ranging types of vehicles and struc­tural circumstances, customer-spe­cific solutions are required.