In this section, you will learn: 

• What is the Railway Microsimulation Model? 
• What types of analyses can be performed using the Railway Microsimulation Model? 

Railway Microsimulation Model (KMM – Kolejowy Model Mikrosymulacyjny)

The Railway Microsimulation Model is an advanced digital tool that provides a detailed representation of railway traffic. Its role is to support decision-making processes related to railway operations. The model is used for analysing railway traffic while accounting for factors affecting train movement, distinguishing it from other analytical tools used within the Horizontal Timetable Project. 

The Model has been developed by Centralny Port Komunikacyjny sp. z o.o. (CPK) and PKP Polskie Linie Kolejowe S.A. (PLK S.A.). Within the Horizontal Timetable framework, the model refines timetable assumptions initially generated using the Passenger Transport Model. It enables detailed verification of timetables, including checking for conflicts in traffic, assessing infrastructure usage and capacity, and analysing resilience to operational disruptions. The result is a timetable that, thanks to comprehensive validation using simulation methods, is free from flaws that could hinder or prevent its practical implementation. 

When developing a timetable, special attention must be paid to railway nodes, which often act as “bottlenecks” due to increased train traffic and the convergence of routes from various directions. In the current phase of work (Q2 2024), the model simulates the largest railway nodes in Poland. This allows for coordinated timetable development, considering constraints in the node areas that may be undetectable in the macroscopic Passenger Transport Model. In the next phase, the model will cover key network sections planned for long-distance passenger and freight trains. Ultimately, the Railway Microscopic Model will encompass the entire Polish railway network, becoming its digital twin. As new versions of the Horizontal Timetable are developed, the Railway Microscopic Model will be continuously updated to reflect infrastructure parameters and model newly planned sections. 

Model Structure 

The Railway Microsimulation Model consists of two main, closely related layers: 

• Infrastructure Layer 

• Timetable and Analytical Layer 

The Infrastructure Layer is a detailed digital representation of railway infrastructure for traffic simulation areas. It includes railway tracks with parameters like maximum speeds, geometric layout, and electrification type. It also models station track layouts and signal control posts, detailing every track, switch, platform, and signal. Crucially, it defines logical dependencies between infrastructure elements, setting rules for railway traffic control, such as signalling device operation times. 

The Timetable and Analytical Layer applies the train timetable to the railway network represented in the Infrastructure Layer. Real-world characteristics of railway rolling stock are also necessary for constructing the timetable. Using these elements and train movement equations, travel times for individual trains are calculated, including necessary technological reserves. Notably, multiple independent timetable versions can be created from a single infrastructure layer scenario. 

The Railway Microsimulation Model as an Analytical Tool 

The Railway Microsimulation Model enables several types of analyses to verify a proposed timetable. 

1. Designing of Timetables
   

The primary analysis involves attempting to create a timetable on the simulated railway network. This analysis verifies whether the infrastructure can accommodate the planned railway traffic, aiming to generate a conflict-free time-distance graph between train routes. 

2. Examination of Capacity Utilisation
    

This analysis examines capacity utilisation by densifying train schedules. It involves filling empty spaces in the time-distance graph with additional trains while maintaining necessary reserves and traffic logic. The goal is to determine how many additional trains the infrastructure can handle while ensuring smooth traffic and required resilience to timetable disruptions. 

3. Examination of Capacity Utilisation of Individual Infrastructure Elements 

This analysis identifies the degree of utilisation of individual infrastructure elements, highlighting those most burdened by train traffic within the analysed timetable. This information is crucial for operational decisions, such as routing trains around nodes and assigning platform edges at stations. It also helps identify critical elements that may cause secondary delays if disruptions occur. Pinpointing these critical points supports the development of comprehensive infrastructure solutions to address these issues. 

4. Simulation of Delays 

A unique feature of the Railway Microsimulation Model (KMM) is its ability to simulate timetable scenarios under “emergency situations.” It uses random delay distributions and nondeterministic simulations by varying delay input parameters to track the propagation or dampening of delays over time, assessing whether initially planned train routes are maintained. Minor delays simulate small incidents, like door issues, while larger delays test the timetable under significant disruptions, such as track closures. This allows for real-world scenario simulation, helping to minimise negative impacts before actual implementation.