By Göte Andersson, November 6, 2024 (Last updated November 22, 2024).
Topic: IoT, Vehicle Electronics, Sensors
Original language: Swedish (this English translation has been slightly shortened, find the original article on page 16-17 here).
Trafikverket aims to eventually equip all railway switches with sensors that measure temperature, motor current consumption, vibrations, and other factors in real time. Sensor data will be processed locally by a Remote Terminal Unit (RTU) and transmitted to a national server.
“We will procure sensors and other equipment in late 2025. This is part of a long-term plan to deploy sensors nationwide,” says Arne Nissen, head of railway switch maintenance at Trafikverket.
Trafikverket’s national sensor network is likely to become one of the largest sensor networks in the country.
Trafikverket wants to keep full control of the sensor network. Its maintenance department will handle investments, expansion, and operations, including the server infrastructure. Sensor data will then be stored long-term in Trafikverket’s cloud service. Additional processing, including combining data from various sources, will be conducted regularly in the central data warehouse. Trafikverket’s IT department will manage the internal cloud service.
“We collect data in our server environment, analyze some data ourselves, and then purchase analyses from vendors who have developed advanced tools. Several companies are interested in providing such analyses. All this will happen in real time,” says Arne Nissen.
“In the near term, we will focus primarily on developing the analysis tools we need to utilize the sensor data we plan to collect in the future,” adds Nissen.
He emphasizes that the capacity and precision of analysis tools will determine how much value Trafikverket can derive from the sensor data.
ElektronikTidningen spoke to Pierre-Henri Bougeant, Head of Digitalization at the railway supplier Vossloh.
He states that infrastructure operators like Trafikverket need to build capacity in four areas:
- Local sensors in railway switches.
- Sensors in locomotives and vehicles.
- Sensors in drones or other data provided by satellites.
- Integration and processing of sensor data in cloud services.
“Collecting and processing data is essentially the new oil. By leveraging these methods, infrastructure operators can optimize the operation of railway networks,” says Pierre-Henri Bougeant.
He also notes that railway companies worldwide are in the process of adopting this new technology.
Pierre-Henri Bougeant highlights the need for standardization to drive down costs.
“I agree with Pierre-Henri Bougeant’s assessment of the benefits of this technology and the drivers for these four areas,” says Arne Nissen.
He points out that Trafikverket is, among other things, experimenting with collecting data from sensor-equipped locomotives and wagons. The benefit lies in early detection of physical defects in the railway network and its substructure. Regular use of drones, helicopters, and satellites to gather data can reveal changes and settlements in the landscape.
How quickly the new technology can be implemented and deliver full benefits remains an open question. Arne Nissen has no forecast.
“We are launching our new data warehouse in 2026. After that, it’s a question of how many years it will take before the technology is available across the entire railway network,” he says.
The cost of implementing the technology and its benefits are the key questions, according to Nissen.
“If we could pay 1,000 SEK per year and sensor, we would be able to deploy the technology on a larger scale, covering significantly more railway switches. However, we are negotiating with suppliers who sometimes ask for 20,000 SEK per year and sensor for their service,” says Arne Nissen.
Sensor Bolts Prevent Accidents
Swedish sensor manufacturer Strainlabs sees a massive market opportunity as railway operators like Trafikverket adopt sensor technology. The company has developed a sensor that prevents bolts from loosening.
Hundreds of thousands of bolts secure rails and railway switches. Strainlabs’ sensor measures bolt tension to ensure they are sufficiently tightened. If bolts start to loosen or become overloaded, the system sends alerts, potentially preventing accidents. This approach is also cheaper than current manual inspection methods.
The message comes from Strainlabs’ CEO, Csaba Madru.
“In my view, Strainlabs is in an excellent position. We have developed a product portfolio for remote bolt monitoring and see markets in the railway, process, manufacturing, mining, automotive, wind power, and solar power industries,” says Csaba Madru to ElektronikTidningen.
The company holds patents for its sensor in the EU, US, and China.
The railway industry has opted for bolted joints to secure rails and switches. A bolted joint consists of bolts and nuts holding the rails together. Washers or flange nuts distribute the clamping force over a larger area to avoid material damage. It is crucial that the bolts are tightened to the correct preload, which Strainlabs’ sensor can measure.
Railway switches are subject to significant stress and vibration. A typical switch handles eight million gross tons annually. Even the ballast (gravel) supporting the switches is affected by railway traffic. As a result, bolts in the joints may loosen.
Extensive manual inspections are necessary under current procedures. Strainlabs’ sensor is embedded in a bolt installed in the existing joint.
The sensor includes a battery that lasts five to six years. It measures the preload force created in the fastener when the bolt is tightened. This allows remote monitoring to ensure the bolt is adequately secured. Strainlabs’ sensor continuously transmits data, including preload force, temperature, signal strength (RSSI), and battery status, every ten minutes to a cloud service.
Strainlabs’ analysis software checks all reported values against set thresholds. This information is continuously reported back to the railway operator, providing updated data. In the future, the sensor will be equipped to measure additional parameters.
Strainlabs collaborates with German company Vossloh, one of Europe’s largest railway switch suppliers.
“Strainlabs’ intelligent bolts are unique. We are not aware of any comparable product,” says Björn Lundwall from Vossloh.
“Vossloh can offer Strainlabs a global market. We sell their product to our customers worldwide.”
Vossloh and Strainlabs and are currently running two joint projects to validate the sensor for different needs.
“Trafikverket has identified a case on the Malmbanan railway where bolts have loosened significantly faster than normal. We want to use Strainlabs’ sensor to find an explanation,” says Lundwall.
Vossloh is also developing a new product to address the issue of thermal expansion in the railway network. The product is an addon to the so called a expansion device, and it will incorporate Strainlabs’ sensor to collect data from bolted joints.
“Vossloh expects testing of Strainlabs’ products to continue until next summer. If the tests are successful, Vossloh could offer commercial products by next summer,” says Björn Lundwall.
How long will it take for large-scale adoption of sensors like those from Strainlabs?
“In my estimation, it could take five to ten years for large-scale deployment to gain momentum,” says Pierre-Henri Bougeant, Head of Digitalization at Vossloh.
Strainlabs was founded in 2014 and launched its product in 2022. The company is currently working on function validation projects with several clients. Approximately 80 million SEK has been invested in the company to date, primarily from venture capitalists.
This article by Göte Andersson explores how advancements in sensor technology, such as Strainlabs’ intelligent bolts, are driving innovation in railway maintenance, enabling improved safety, cost efficiency, and real-time data analysis. Read original article in Swedish: Online PDF, pages 16-17.
