Remote geotechnical monitoring of rail tracks: your queries answered

Interest in wireless systems for rail infrastructure monitoring continues unabated, as evidenced by the interest in our recent sponsored Tech Talk Webinar on the subject. Hosted by our UK Sales Manager Matt Azzopardi and featuring Worldsensing Application Engineer Angela Lluch Gracia along with Tim Clegg, Commercial Manager at Geosense, the session led to a host of questions that couldn’t be answered in the time allotted.

For those of you who attended the session—or are interested in listening again and finding out more—this blog covers their answers to the questions that came up during the event.

Rail monitoring questions

How do you install tiltmeters in the ground?

In the case study you used, did you transfer the data from the Automated Total Station (ATS) with LoRa or the wireless system?

How do clients typically visualize the data recovered from the inclinometers and tilt sensors when they use it to inform decisions?

What do you do if there is a lack of terrestrial connectivity at the site you are deploying to?

Who makes sense of this data? Are carriers capable of doing it themselves?

Could we get raw readings of sensors by Application Programming Interface (API)?

Do the sensors transmit any noteworthy metadata?

What is the biggest challenge affecting accurate remote and real-time monitoring of the areas and infrastructure surrounding rail tracks?

Does your technology monitor embankment slippage, wall cracks, tunnel convergence and rock fall simultaneously and at the same degree of accuracy?

Where is the data stored if it comes through in real time? Is it on our system or Worldsensing’s? How long is it worth keeping data until it loses its value?

Which is the single most important monitoring parameter?

How do you install tiltmeters in the ground?

Angela Lluch: You don’t need to install them in rock, provided you can ensure the device is not affected by meteorological effects. For that, it might be necessary to reach down a certain depth from the surface.

In the rail monitoring case study you used, did you transfer the data from the Automated Total Station (ATS) with LoRa or the wireless system?

Tim Clegg: The client used a system provided by the ATS provider. The data however was sent into the same platform as the sensors collected by the LoRa system.

How do clients typically visualize the data recovered from the inclinometers and tilt sensors when they use it to inform decisions?

Tim Clegg: Clients typically will get the data sent to visualization software which can graphically present it to be more meaningful. Alarms can be added to alert stakeholders to any movements outside expected parameters. You can contact Geosense or Worldsensing for a list of visualization packages that work with the Worldsensing equipment.

What do you do if there is a lack of terrestrial connectivity at the site you are deploying to?

Tim Clegg: Whenever there is a lack of Internet connectivity the data remains recorded on both the loggers and the data server. On top of that, provided the data is retrieved by MQTT, there will be a queue of stored messages that will be sent out once the connection is back. The MQTT communication protocol will be implemented in the firmware version 2.6, to be launched soon, for the CMT Edge and CMT Cloud architecture.

Otherwise, the user would have to download the data manually by logging remotely into the data server or by manually downloading the data from loggers via the Worldsensing app.

Who makes sense of this data? Are carriers capable of doing it themselves?

Tim Clegg: Data interpretation usually relies on experts’ criteria. It is necessary to be aware of the context, design and the site conditions to make a proper judgment. In that sense, a data platform can be extremely useful to manage and visualize the output of multiple sensors and the data obtained from different monitoring techniques.

Could we get raw readings of sensors by Application Programming Interface (API)?

Tim Clegg: Yes, with API calls it is possible to collect the raw data of the sensors, and with the implementation of MQTT it’s possible to do so while having a much lower impact on processing capacity. On top of that, the user would be able to retrieve old messages and not only the last reading.

Do the sensors transmit any noteworthy metadata?

Angela Lluch: Every data logger reports readings according to the sampling rate you have set, and every seven hours it also reports its health status, for troubleshooting.

What is the biggest challenge affecting accurate remote and real-time monitoring of the areas and infrastructure surrounding rail tracks?

Tim Clegg: First, it is important to select the correct sensors to monitor the required parameters. Second, a high-quality install by a monitoring contractor is required to ensure that the correct sensors provide accurate data. Third, selecting a robust and capable wireless system, such as the Worldsensing LoRa platform, will ensure that the sensors send data reliably to stakeholders.

Does your technology monitor embankment slippage, wall cracks, tunnel convergence and rock fall simultaneously and at the same degree of accuracy?

Angela Lluch: The accuracy is determined not only by the sensor type and brand but also by the Worldsensing loggers that collect, store and broadcast the data. You can check the specifications of our devices on the Worldsensing website.

Where is the data stored if it comes through in real time? Is it on our system or Worldsensing’s? How long is it worth keeping data until it loses its value?

Tim Clegg: The data is stored first on the node, so if radio communication goes down you can hard wire into the node to retrieve it. Also, the data that is communicated via radio is also stored on the gateway, which—if there is no signal—also allows you to download the data directly. If the data is sent to third-party software, the data is usually saved on the cloud platform as long as the subscription is paid. Typically, the time depends on the project and need for monitoring.

For example, for new structures clients may want to install for just the construction phase—or they may choose to do structural health monitoring for years to come.

Which is the single most important monitoring parameter?

Angela Lluch: I am not sure if the question is referring to the most important parameter of the track geometry or of the surroundings, but I would say that there is not always a single critical parameter. It will depend on the anomalies detected on the area; however, pore water pressure and water level turn out to be critical parameters when it comes to slope stability.

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