The article is devoted to the analysis of the effectiveness of the DTN (Delay Tolerant Network) system in a communication network on a railway line. Trains act as moving objects that are sending and receiving messages to/from an external network. As well trains may transmit telemetry, collected during movement. The article presents data on effectiveness of the DTN network in terms of reducing the delay in message delivery, reducing the delay in transmitting telemetry, and increasing the total number of messages in the railway scenario. The data on the theoretical efficiency of the DTN system is presented, including the results of the generation of many maps of railway networks and the corresponding train schedules. An analysis of railway lines with various loads and different coverage of mobile network was made. These models are based on real railway maps and train schedules. Effectiveness of DTN during migration to networks of a higher data rate (5G) and networks with satellite connection of trains is discussed.