###### Abstract  
The physical characteristics of fifth generation (5G) cellular network wavelengths result in quicker attenuation and smaller base station (BS) coverage area, which in turn, cause BSs to naturally transform into small cell BSs (SBSs). However, in the case of fixed-rail transportation, they often cover long distances when deployed and pass by multiple SBSs; hence, the connection of the terminal equipment in these forms of transportation is subjected to frequent handovers. Therefore, it is important to address the issue of identifying suitable SBSs for each handover such that a certain level of service quality and non-interruptible transmission can be achieved. In the present study, we proposed a new handover selection algorithm named the toss-and-catch algorithm. By means of an efficient SBS selection mechanism and configuration settings, the algorithm selects suitable SBSs to ensure reliable transmission and non-interruptible handovers. Meanwhile, with the assistance of an overload support mechanism, the algorithm is able to resist changes in channel environments under most conditions. In order to apply our results in more realistic channel environments, we performed all-inclusive simulations based on different symmetric fading channel environments, with the aim of developing more practical SBS selection and handover methods for mobile terminal equipment. The multitude of simulation results indicates that from the perspective of terminal equipment in fixed-rail transportation, under most conditions, the performance of the toss-and-catch algorithm in terms of signal quality and handover connection was superior to those of other conventional methods. For example, the toss-and-catch algorithm outperformed the random SBS selection method in a typical fading channel environment (e.g., Nakagami-1 fading), achieving, on average, an approximately 28% improvement in signal quality, an approximately 50% reduction in the disconnection rate for handover connections, and an approximately 71% improvement in processable load ratio. These results indicate that the toss-and-catch algorithm allows for a greater number of suitable SBS handover candidates to be identified, making it a promising SBS handover selection mechanism for 5G fixed-rail transportation networks. e +
Footnote †: journal: Applied  
and maintain, while also being more economical, making dense deployment the preferred approach for SBSs [1]. However, SBSs also provide a smaller coverage area and it can sometimes be difficult to maintain good service quality for users. In the case of fixed-rail transportation (such as trains, high-speed rails, and subways), they often cover long distances when deployed and pass by multiple SBSs, hence the connection of the terminal equipment in these forms of transportation is subjected to frequent handovers, and it is crucial that we achieve reliable transmission and non-interruptible handovers when identifying the appropriate SBS for each handover. The increasingly widespread implementation of 5G networks and emerging real-time applications has brought the issue of seamless mobility to the forefront. Against this backdrop, it is important that we design appropriate algorithms for the handover process. With the objective of facilitating external communication transmissions involving the connected devices of users in fixed-rail cars, the cars examined in this study are each treated as a single connection unit with a \"connection export equipment\" that connects them to external networks.