FORMATION OF A TECHNOLOGICAL PROCESS MODEL FOR THE LOCAL OPERATIONS SUBSYSTEM OF A MARSHALLING YARD STATION USING THE MATHEMATICAL APPARATUS OF COLOURED PETRI NETS

The article examines the formation of a technological process model for the local operations subsystem of a marshalling yard using the mathematical apparatus of Coloured Petri Nets (CPN Tools). The primary focus is on evaluating the effectiveness of this approach in modeling complex dynamic processes characteristic of railway station operations. Coloured Petri Nets not only allow differentiation of objects of various types using coloured tokens but also enable the modeling of temporal aspects of processes through different statistical distributions, including exponential, normal, and Erlang distributions. This enhances the flexibility and accuracy of the model. Simulation results indicate that the average queue length of wagons awaiting dispatch depends not only on the mean duration of shunting locomotive operations but also on the variance of this duration. While it is expected that an increase in the mean operation time leads to longer queues, the impact of variance is less obvious. Increased volatility disrupts the rhythmicity of the process, creates bottlenecks, and causes the accumulation of delays in the system. This finding suggests that instability in operation durations can have a significantly more negative impact than even a lack of shunting capacity. Considering this factor is critically important for effective planning of railway yard operations. Moreover, the results highlight that not only operational planning but also the precise execution of operations in practice plays a decisive role in system performance. Notably, such an analysis would be challenging without the use of Coloured Petri Nets, which enable the modeling of complex interactions between different types of objects (locomotives, wagons, tracks) while accounting for the temporal characteristics of processes. This confirms the effectiveness of CPN Tools as a powerful instrument for analyzing and optimizing technological processes in railway systems.