In case of a tunnel accident, the hazards for passengers and rescue services are not only fire and smoke but also power-voltage on overhead lines. A fast evacuation is crucial and the railway service operator must ensure that overhead line is disconnected and earthed before rescue services enter the tunnel.

The emergency tunnel earthing system of overhead line is an integrated automatic system that allows the safe management of the disconnectors and the earthing of the overhead line in the tunnel.

The system allows the disconnecting and earthing by a remote Control Centre or by local control and display unit installed in all tunnel accesses, with a simple and comprehensive way for operators and rescue services.

This system is the response of technical specification for interoperability relating to “Safety in railway tunnels TSI – SRT” in European railway systems (2008/163/EC); the EU specification requires a way of earthing the overhead line for tunnels over 1 km long.

This system is designed for the safety earthing of the overhead line in short time under emergency and the achievement of high levels of SIL (Safety Integrity Level) and can be realized in different version according to specific requests from local railway company, in particular:

• Standard configuration with no SIL requirement
• SIL3 certified according to IEC 61508, IEC 61511
• SIL 4 certified according to EN 50126, EN 5128, EN 50129