Some say a picture is worth a thousand words, some say the devil is in the detail. Here I'll show you a little of both, as we examine a rockfall, or more accurately a series of rockfalls, that happened at one of our clients who use our rockfall detection application.
Our fiber optic sensing detection equipment was freshly installed to protect this railway. The equipment looks for vibrations via trackside fiber optic cable using a technology called Distributed Acoustic Sensing (DAS) - you can find more on how DAS works here.
The end result is an automated system, that constantly listens out for the characteristic vibrations caused by a rockfall or landslide. It does this tirelessly and automatically 24/7. When the sensing device detects a rockfall, it sends an alert including the exact location to the operations control team so they can act. The method of sending the alert varies by client preferences, but in this case they use e-mail and SMS message. Other options include integration with existing systems, web dashboards and more.
The screenshots below show the vibration data recorded for these events over a short length of track and time. The brighter the colours, the higher the vibration intensity. Our algorithms listen to this data in real-time and the red diamond shows when the algorithm has detected a rockfall event and sent an alert for action to the network operator.
Rockfall Data Review
Here is the timeline of the rockfall events at this location:
Sunday 07:51
First moderate rockfalls impacts detected (x2). Automated rockfall alarm generated.
Rail operations team sent alerts by email and SMS.
Sunday 20:04
Small rockfall impact observed. Automated rockfall alarm generated.
Rail operations team sent alerts by email and SMS.
Sunday 21:41
Small impact was observed.
Automated rockfall alarm generated.
Rail operations team sent alert by email and SMS.
Monday 06:52
Large rockfall impact was detected.
Automated rockfall alarm generated.
Rail operations team sent alert by email and SMS.
Monday 07:20
Another large rockfall impact was detected
Automated rockfall alarm generated
Rail operations team sent alert by email and SMS.
As this route carried no Sunday traffic, the track inspection of the location higlighted was carried out before the first scheduled train.
The Rockfall Found
The rock fence was breached by a substantial rockfall blocking the track. The weather at the time was foggy/misty as seen in the photo. Without the rockfall detection being in place it is possible, perhaps probable, that a train would have been unable to stop in time and would have struck the obstruction. Our alerts ensured that this didn't occur enhancing safety of the network.
The result was zero harm to staff, passengers, rolling stock and the environment.
Our rockfall equipment protects up to 80km / 50 miles of track from a single sensing unit. For more intelligent rockfall detection without installing and maintaining a forest of trackside sensors contact our team.
