Eurostar tunnel has intelligent fans

Ventilation and safety for the new Cross London Channel Tunnel Rail Link is controlled by a dual redundant system of programmable automations controllers (PACs) which link into the SCADA (supervisory control and data acquisition) located at the Eurostar control centre based at Ashford in Kent.

There are three new tunnels on the new high speed link that runs from Ebbsfleet in North Kent to the newly refurbished St Pancras station, passing under central London and the River Thames. The tunnels are twin bore, one for each direction of travel, with regular cross passages that facilitate escape to safety in the event of an incident.

Ventilation and escape/access are the keys to tunnel safety and Rail Link Engineering entrusted the control system for this to Johnson Controls who chose Mitsubishi Electric as their key technology supplier. Several different architectures were considered for the project, the one finally selected being a unified dual redundant network running all the way from the Ashford control centre to St Pancras and back again.