This article describes quality-of-service (QoS) tests at railway customer trial sites. The QoS tests consider the GSM-R network which has been agreed to by the UIC to be the track-to-train communication platform for the current and future railway applications. The performance of the various applications themselves will not be the focus hereafter. Based on the experience gained during several test campaigns on railway operator’s trial tracks in Germany, France, Switzerland and Sweden, some recommendations are given concerning the test and evaluation strategy of QoS criteria. Used test tools and typical QoS values, measured at customer trial sites which are equipped with Siemens GSM-R infrastructure, are presented. The tests‘ results demonstrate that in well-planned radio environment all known railway QoS requirements will be fullfilled by the installed GSM-R equipment.