Providing seamless connectivity to mobile users on-board railway vehicles is quickly gaining ground as part of the society in motion. Today, the main challenge for academia and industry coping with service quality improvements for smartphone users stems from a few tens of decibels vehicle penetration loss impacting mobile communication frequencies. To deal with this, we demonstrate two designs such as frequency selective surface- and amplify-and-forward repeater-aided railway vehicles. In this paper, we use the rank-based nonparametric inferential approach to assess the service quality improvements of various smartphone placements' on-board railway vehicles. As part of the presented framework, we demonstrate the problem of characterizing vehicle penetration loss along particular railway tracks. All in all, the proposed framework is evaluated on inter-city and regional trains as well as over two heavy-traffic railway environments in Austria. The smartphone users placed next to frequency selective surface structures as well as in the proximity of an amplify-and-forward repeater are shown to gain in coverage the most.