Implementation of a DMR-Based Digital Radio Communication System in the "Kamchik" Railway Tunnel

This study investigates the implementation of a Digital Mobile Radio (DMR)-based communication system to modernize the obsolete analog radio networks in the 19.2 km-long Kamchik railway tunnel in Uzbekistan. The primary objectives are to enhance safety, reliability, and operational efficiency in this critical transportation corridor. The research involves comparative analysis, field testing using Hytera MD-785 digital radios, and simulation modeling. The proposed system integrates repeaters, omnidirectional antennas, and optical fiber lines to ensure secure, real-time communication between train operators and dispatchers. Experimental results demonstrate significantly improved signal coverage, energy consumption reduced by up to 40%, and increased scalability of the communication infrastructure. Tunnel-Specific challenges such as signal attenuation and electromagnetic interference are addressed through optimized equipment placement and system configuration. The system’s performance is benchmarked against established digital standards such as TETRA and GSM-R, with DMR demonstrating technical superiority, cost-efficiency, and high resilience to environmental conditions. Recommendations include the deployment of repeaters at 1200-meter intervals and the use of Ethernet and fiber-optic backhaul for reliable network integration. The proposed solution offers a scalable and adaptable model for upgrading railway communication infrastructure in Uzbekistan. Additionally, the system enables automated train control, real-time monitoring, and supports future enhancements in operational safety. The study also evaluates the environmental durability and long-term reliability of the equipment, confirming its suitability for tunnel-specific conditions.