Remote Telemetry Units (RTU) are helping rail operators maintain efficiency and safety at a time when, outside the coronavirus crisis, passenger numbers are increasing. Here, Philippe Aretz looks at how best to access these benefits
Up until the world was faced by the current global pandemic, a record number of passenger journeys were made on English, Scottish and Welsh railways. In fact, a survey by the Office of Rail and Road showed that 1.76bn journeys were completed on Britain’s rail network during the 2018-19 calendar year, a 3.0 per cent rise compared to the previous year.
The continued rise of passenger numbers places increasing pressure on an already stretched network, which means that maintenance and monitoring programmes are an essential element of ensuring rail assets operate safely, reliably and efficiently.
At the same time, companies need to deliver returns to their stakeholders, and any disruption or delay to the timetable can result in lost revenue. With fines for late or cancelled trains, operators have a vested interest in managing reliability. There is also a need to constantly monitor the environmental impact of operations and above all else, ensure the safety of staff and passengers.
Data is critical to meet these challenges and the most appropriate device to collect and process this ‘data’ is the RTU or Remote Telemetry Unit. These devices have a long-proven record of sitting on track, station, signalling and level crossing assets where they collect, store and act upon data, and can do so reliably and securely in the harshest of environments that some of the world’s railway lines run through.
In these applications, RTU’s are effectively computers in the field. They collect data locally, act upon it immediately, report data to the central control room and maintain a local historical store as an additional backup. The RTU is the device sitting between the Control Room and the field instruments, which provides a low latency response to changing site conditions as well as performing data filtering. The RTU ensures that only key, critical information is passed via the narrow communications links, minimising data throughput but maximising useful information received.
The specific types of roles they carry out include: power distribution monitoring and control, remote signalling sub systems, point and crossing monitoring, track and station condition monitoring as well as passenger information systems. Alongside this, RTUs can provide train/track location system monitoring and control, and driverless train early warning systems.
Case file: Control Switch Point Heaters for Major European Rail Network
TBox RTUs were selected by a major European rail network to provide point heating condition monitoring. The network is located in a country where there are extreme weather conditions and as such the operator is required to have workers in over 700 railway stations on call around the clock for clearing snow or ice from switch points to prevent them from freezing or blocking with snow.
Following a review, the track maintenance team decided to install automatically controlled heating systems at all strategic locations to reduce the sizeable cost of manpower. In addition, hundreds of switch points were fitted with small heaters powered by gas or electricity. Using a complex algorithm based on data from temperature and humidity sensors, ice and snow on the rails is now detected automatically. A complex PID control system starts the heaters to prevent the build-up of snow or ice on the switch points.
In each railway station, automation is performed by a TBox RTU located in a control cabinet. Depending on the complexity and size of the station, one or more remote I/O modules are provided as sub-stations in the field to operate and monitor a group of switch point heaters. Via a local RS 485 network that can be up to several kilometres in length, the sub-stations handle the measurement and control tasks of the individual heating systems. Despite electrical interference from passing trains, automation and communications remain perfectly stable. Each sub-station has its own operating console for maintenance and manual control. Only one device is required for communications and remote control of the heating systems
All the data (correct sensor operation, set-points, outside temperature, gas pressure, present consumption, etc.) from the RTUs is transmitted to a central station using SCADA software and an Ethernet network with TCP/IP protocol. The WAN (wide-area network) uses fibre optics and Ethernet communication. For redundancy and safety, each TBox RTU has its own GSM modem that can be directly addressed for maintenance or control purposes. It can also be used to send e-mails or alarms to GSM mobiles.
Benefits of the telemetry units for the train operator are that they deliver an extremely fast return on investment due to the significant savings in electricity and gas consumption by the fully controlled heating system. Complete remote control of each railway station, eliminating the need for local personnel to clear the switch points, enabled them to be deployed to other tasks.
These kinds of RTU systems provide utmost reliability of the hardware and software components, which was essential on this project due to the extremely harsh environment. In addition, the system allows for local data logging of events and recording energy consumption, temperatures, and equipment operating time, which is proving to be valuable information for the management team. The system provides automatic alarm signalling to key maintenance personnel in charge of the switch points.
In addition to providing safety and reliability, heating systems can realise major savings in energy costs through automation. Using a programmable device like the TBox RTU provides significant savings compared to older techniques, in which the heaters are either constantly on for the entire winter or operated by a thermostat.
Advances in RTUs
In terms of the basics, the key features needed in any RTU are; resilience to the site environment, an ability to operate with minimal drain on local power resources and the processing power to perform any local control algorithms autonomously. It is also beneficial for an RTU to have extensive diagnostics capability and a low MTTR (Meant Time To Repair) to reduce the time required for technicians to spend on site, improving both efficiency and personnel safety.
Being able to perform autonomous control in real time and then report to SCADA that it has everything under control is an advantage; staff at the SCADA interface can ‘supervise’ the operations by setting new KPIs (Set Points) or updating instructions (open/close this, start/stop that or switch on / off – as in the track point heaters, for example) for RTU’s to then act upon and manage locally.
In addition, because RTU’s do everything locally, if communications break down they continue to run, maintaining a historical log, and reporting back later. In remote track and tunnel locations this is an essential part of keeping maintenance teams informed and being able to trend data. For example, the data that the RTU collects can be used to support maintenance decisions and to verify that safety obligations are being adhered to. Although most RTU’s in the rail network are only used for operations they can support maintenance teams, health and safety initiatives and environmental management. This ability to provide accurate, real time data allows Train Operating Companies to make better, more informed decisions. Looking to the future RTU’s, which are already ‘mini PCs in the field’, can transform an aging rail asset into a ‘smart’ asset. This is possible by fitting an RTU to allow it to trend, interpret and act on data collected from that older asset.
Cyber security is also a key requirement from an RTU. TBox RTUs embed all features to protect the asset from external attack by using login mechanism, data encryption, firewall, denial of service protection and brute force attack protection.
The way forward
Our switch point heating and catenary de-icing systems now provide energy-saving heating and de-icing for the rail infrastructure in some of the coldest parts of the world, which ensures cold-weather safety on both rails and stations. The applications include electrical point heating, geothermal point heating, overhead wire de-icing, contract rail de-icing and platform and stairs de-icing. They are installed as complete efficient energy saving solutions or as single components to existing systems and widely used in all ‘cold’ European countries, USA and Canada. They provide excellent return on investment and long-life cycle.
As RTUs evolve and become more powerful they will continue to help the rail sector deal efficiently with record numbers of passengers, once the coronavirus epidemic has been beaten. Innovation will help drive this change; it is already possible to deploy RTUs on a diverse range of rail assets, whatever its size or age. Inbuilt redundancy and resilience are helping to avoiding system failures. At the same time, improvements in processing power and throughput are helping RTUs keep up with increasing demand for data.
The rail sector is defined by its geographically spread assets and multiple process all of which generate massive amounts of data; key to ensuring this data helps efficiency and performance is being able to capture and interpret it in real-time and convert it into useful management information. Latest, ruggedized RTU technology focuses specifically on that, helping rail operators meet their investor and customer commitments.
Now is a good time to look at the benefits of RTU’s and get a programme in place ready for when things return to normal as they surely will. It is those companies that grasp this opportunity that will be ready for the upturn in passenger numbers.
Philippe Aretz is Channel Sales Director at Ovarro, previously Servelec Technologies. Ovarro is headquartered in Sheffield, UK, with offices also located in Reigate, UK, Denmead, UK Melbourne, Australia, Waterloo, Belgium, Calgary, Canada, Lyon, France and Abu Dhabi in the United Arab Emirates and Malaysia. For more than 40 years, the company’s hardware and software products, systems, and consultancy services have been trusted by the world’s leading companies across sectors such as water & wastewater management, oil & gas, transportation, communications & broadcast, and energy.