The Impact of Track Gauge on the Stability of the Tram with Increasing Speed

Objective: to substantiate the track gauge for straight sections of tram lines, taking into account the type of rails and inclines, ensuring stability at increasing speeds to meet the development prospects of urban rail transport. Methods: multivariate computer simulation was performed using a specially developed model of the most widely used three- section tram “Vityaz- M” in the Universal Mechanism software package. The simulation varied the track gauge (from 1518 to 1538 mm), rail type (R65 railway rails and RT60 grooved tram rails), inclination (1:20 and 0), and travel speed (10–80 km/h). The lateral acceleration of the body and unsprung masses, as well as the guiding forces in the approaching wheel pairs, were analyzed. Results: it was found that at speed up to 40 km/h a track gauge in the range of 1518–1538 mm does not significantly affect the lateral acceleration of the body remaining below the standard limit of 0.2 m/s². As speed increases to 50–70 km/h, changing the gauge from 1524 mm to 1520 mm reduces lateral acceleration of the outer section body by 34–44 % depending on the rail type and inclination, while the total guiding forces increase by 30–50 % ensuring the guiding function of the track gauge. Further narrowing the track gauge to 1518 mm provides a slight additional acceleration benefit, but is accompanied by an increase in guiding forces to values that cause increased wear and increases the risk of wheel set seizure. Practical significance: the feasibility of switching to a standard track gauge of 1520 mm for newly constructed and reconstructed high-speed tram lines is substantiated. Switching to a 1520 mm track gauge will improve ride stability, passenger comfort, and reduce lateral wear of the rails and wheel flanges.