Assessment of the Applicability of a Thawing-Guided Drainage System for Old Railway Tunnel Icicle Prevention in Cold Weather

As train failures from icicles annually recur in old railway tunnels in cold weather, fundamental measures to prevent the formation of icicles within the tunnels are necessary for the safe operation of trains and efficient maintenance of old tunnels. This study develops and tests a thawing-guided drainage system for old railway tunnels. The proposed system consists of heating panels, supporting stands, and the drainageways for discharging leaked water. A heating panel is composed of a film heater, thermal insulator, and a steel plate. The heater installed on a steel plate supplies the heat source to prevent icicle formation. This system uses a low-power module lining structure, which fundamentally prevents the formation of icicles from cracks in old railway tunnels and induces the drainage of thermally melted icicles to the outside of the track. A prototype system was installed in the Seungbu tunnel (a railway tunnel) and monitored over 3 weeks in winter from 22 December 2021 to 12 January 2022. The icicle prevention and guided drainage performances were verified at an ambient temperature of about −10 °C, with an internal temperature for maintaining the system above 0 °C over the whole test period. The proposed system is judged by the fact that the applicability of the developed system has been verified in consideration of the following three aspects: usability in the operational railway line, effectiveness through icicle prevention performance, and operational safety which does not interfere with train operations.