Stowehill Tunnel is on the West coast main line and at present has a maximum line speed of 120mph.
To allow this to be raised to 150+mph, four vertical pressure relief shafts are being excavated from the surface above the tunnel to break out into adits constructed through the existing lining.
To protect the tunnel and to ensure trains can continue to operate safely, ITM have installed a comprehensive array of instrumentation, both on the tunnel lining and the track itself at each adit location.
Data is collected every 10 minutes, 24 hours a day, and monitored via our I-Site and AlertTM' software suites. If any of the user-configurable alarm thresholds is reached, then the duty engineer is automatically informed, day or night.