2026 , Volume 31, № 4, p.20-30

The paper presents and analyzes a mathematical model of a mountain-pass railway section where pusher locomotives are required for uphill freight trains. This makes it one of the bottlenecks on the Trans-Siberian Railway. The section runs along the shore of Lake Baikal, which imposes strict environmental constraints on both its operation and any potential upgrades. The model is a semi-open queuing network which include fork and join nodes. It consists of three types of nodes: standard nodes simulate train movement between stations and within stations; join nodes describe the coupling of pusher locomotives to trains; fork nodes represent the uncoupling process. A marked markovian arrival process describes the arrival of transit trains of different categories. The routes of the trains and pusher locomotives are captured using multiple request types with individual route matrices. The mathematical model is implemented as a simulation model and analyzed numerically. The results obtained lead to the following conclusions. The section has a 12 % capacity reserve. However, further increases in capacity will require expanding the infrastructure at Slyudyanka–2. The station is located in close proximity to the shoreline, which significantly limits modernization options. The longest freight train stopping times are observed at Slyudyanka–1 and Slyudyanka–2 stations, necessitating an assessment of the insulation quality in these areas to minimize the ingress of contaminated wastewater into Lake Baikal. The number of pusher locomotives required to maintain normal operation under future increasing traffic demand is also estimated.