Dynamic Assessment of a Tunnel Overhead Contact System with Elastic Arm Support

Tunnel electrification systems employing elastic support arms offer an effective solution for maintaining a suitable pantograph–catenary interaction under restricted clearance conditions. This paper presents a dynamic assessment of a tunnel overhead contact system (OCS) inserted within a conventional flexible catenary through dedicated transition zones. The tunnel section employs twin contact wires supported by elastic arms supports, enabling compatibility with the surrounding electrification infrastructure while accommodating the geometric constraints imposed by tunnel environments. System performance is evaluated through numerical pantograph–catenary interaction simulations in accordance with standard assessment criteria, including mean contact force, standard deviation of contact force, and maximum contact force. The results indicate stable current collection behaviour over the entire operating speed range considered, from 80 to 160 km/h, with all force-related performance indicators remaining within the prescribed acceptance limits. These findings demonstrate the suitability of tunnel electrification systems based on elastic support arms for railway operations up to 160 km/h. Furthermore, the proposed modelling and simulation methodology proved effective for evaluating the dynamic performance of this electrification concept, providing a robust framework for future tunnel electrification projects and design optimisation studies.