Ref. Ares(2018)4856304 - 21/09/2018 Deliverable D1.4 Report on microseismic monitoring and early warning system Project acronym: GoSAFE RAIL Starting date: 01/10/2016 Duration (in months): 36 Call (part) identifier: H2020-S2R-OC-CCA-04-2015 Grant agreement no: 730817 Due date of deliverable: April 2018 Actual submission date: 14-05-2018 Responsible/Author: Yme Asgeir Kvistedal - YK Dissemination level: PU Status: Issued Reviewed: NGI and ROD-IS GA 730817 Page 1 | 25 Document history Revision Date Description 0.1 13.04 First draft 0.2 19.04 Internal revision by NGI 0.3 11.05 External revision by ROD-IS 1.0 14.05 First issue Report contributors Name Beneficiary Short Name Details of contribution Yme Asgeir Kvistedal YK Author Frode Sandersen FS Author Asgeir Olaf Kydland Lysdahl AOL Internal review Lorcan Connolly External review GA 730817 Page 2 | 25 Table of Contents 1. Executive Summary ................................................................................................................ 4 2. Abbreviations and acronyms .................................................................................................. 5 3. Background ............................................................................................................................. 6 4. Objective/Aim ......................................................................................................................... 6 5. Introduction ............................................................................................................................ 7 6. Rauma Line ............................................................................................................................. 9 7. Detection and warning system - hardware .......................................................................... 12 8. Processing and detection - software .................................................................................... 16 9. Data examples from Rensken ............................................................................................... 19 10. Rockfall simulation tests ....................................................................................................... 20 11. Discussions ............................................................................................................................ 23 12. References ............................................................................................................................ 24 GA 730817 Page 3 | 25 1. Executive Summary A prototype rockfall and landslide warning system has been installed at a high frequent rockfall site on the Rauma line, north-western Norway. The system is based on a wireless microseismic sensor network, and uses a combination of geophones and magnetometers to identify vibrations in the railway line, generated upon impact of falling rocks or landslide debris. The aim of the system is to identify when events with potential to generate obstructions or damage to the track has occurred, and to issue an automatic warning to the driver of the next passing train of the potential hazard. A set of algorithms to identify the different types of events generating vibrations in a railway line has been implemented. The ability to identify rockfalls were tested on an abandoned track section, using a sledgehammer to simulate impact. During these tests the system automatically identified all impacts sufficiently strong to generate a shockwaves in track. Detection of landslides is based on an algorithm previously used for detection of avalanches, having a proven track record. Identification of trains and rolling-stock is achieved using magnetometers, and has so far had an absolute success rate on site. At the time of writing the prototype has been in operation for a little more than four months, and during this period there has not been any naturally occurring rockfalls or landslides. An extended testing period is needed before making a final conclusion on the reliability and applicability of the technology as a warning system. The technology is reliable, has low maintenance requirement and is easy to install onsite without interfering with normal traffic. GA 730817 Page 4 | 25 2. Abbreviations and acronyms Abbreviation / Acronyms Description Geohazard Naturally occurring dangerous phenomenon that may cause loss of life, injury or other health impacts, property damage, loss of livelihoods and services, social and economic disruption, or environmental damage. Risk The combination of the consequences of an event or hazard and the associated likelihood of its occurrence. NGI Norwegian Geotechnical Institute BaneNor Norwegian National Rail Administration Rensken The GoSafeRail landslide and rockfall warning system test site. GSM-R Global System for Mobile Communications – Railway CTC Centralized Traffic Control ERTMS European Rail Traffic Management System GA 730817 Page 5 | 25 3. Background The present document constitutes the Deliverable D1.4 “Rockfall and landslide warning system on the Rauma Line” in the framework of the WA 3.1, task 1.2 of CCA 04-2015. 4. Objective/Aim This document has been prepared to provide documentation on a prototype system for object detection on railways, developed as part of the GoSafeRail project. GA 730817 Page 6 | 25 5. Introduction Geohazards such as landslides, rockfalls and avalanches pose significant risk to railways in many countries. This is especially true with older infrastructure, built at a time when available mitigation measures were limited. At some locations geographical challenges and cost constraints left no choice but to build railways through areas with known geohazards. As many of these lines still follow the same routes as when first built, the associated hazards persist today. In the future climate change is also expected to alter the geohazard risk at given locations, as more rain is likely to trigger more landslides, while less snow will result in fewer avalanches (Aunaas, 2016). Physical mitigation measures such as barrier walls and rockfall nets are successfully used to improve railway safety. Geohazard risk mapping has however shown that when the situation is significantly complex these measures become costly and difficult to dimension (Sandersen, 2016). Moving the line and building tunnels are in many cases the only permanent physical alternative. Figure 1: On the 9th of June 1926 a major landslide hit the Rauma line by Verma station. The landslide crossed the line twice, on both sides of the horseshoe turn in "Vendetunellen" Monitoring and warning systems are cost-efficient alternatives when permanent mitigation measures become difficult. These systems often need to cover sections of several kilometres and GA 730817 Page 7 | 25 should be able to detect all foreseeable geohazard events. In addition they need to work during all weather and seasonal conditions, and should ideally be easy to install and maintain. Slide detector fences have been used as a warning system for avalanches and rockfalls for many years. These are relatively simple systems where a close circuit is broken when a wire in the fence is cut upon impact. The problem with these installations is that they require personnel to enter a potentially hazardous area to repair a broken fence, before regular operation can continue. Many of these systems are thus left inactive. Pilot vehicles are sometimes used to check a line ahead of a passing train. This will reduce the overall capacity on the line and could unless fully automated become costly to deploy on a large scale. In the future drones are expected to become an alternative to pilot vehicles. This technology is however also subject to limitations, as most geohazard events are associated with severe weather conditions and limited visibility, making flying and visual inspection challenging. In more recent years different technologies have been used to detect track obstructions. Cameras and radars can automatically monitor track sections for objects that could pose risk to trains. Although efficient, these technologies are limited by line of sight and mostly applicable on hotspots such as stations and crossings. Geophones and fibreoptic cables have been used to detect possible obstructions through vibrations in the tracks. NGI installed the first prototype rock and ice fall detection system based on an array of geophones in 2004 (R. Cleave, 2009). This system used a standard seismic data acquisition unit and custom developed software for classification of events. The installation contained 24 geophones, mounted with 25 meter spacing alongside an exposed section of the Nordland line in northern Norway. The system was operational over a five year period, before eventually discontinued due to maintenance issues. Canadian railways also operate a few similar systems produced by Weir-Jones (Nedilko, 2016). Optical methods can be used to detect and locate vibrations and deformations along a fibre-optic cable. This method has been applied along roads and pipelines, and proposed as a solution for object detection on railways (Maloney, 2004). Both fibre-optic detection and wired geophone arrays require cables alongside the track, and are thus cumbersome to install and maintain. Analogue geophone cables are also subject to electrical interference and signal loss, limiting the possible length of a single system (R. Cleave, 2009). This report describes a wireless geophone-based rockfall and landslide detection system, developed as part of GoSafeRail. The prototype installation