In most railway organisations, the telecommunications function is one of the smallest when compared to other engineering disciplines. However, from the earliest days of railways, telecoms services have always been very important, both for normal and emergency working purposes.

Today, with digital rail, traffic management, in-cab signalling, big data, customer information, the remote monitoring of assets and passengers requiring to be always connected via Wi-Fi, the railway telecoms network is, strategically, more important than ever.

Rail Engineer recently met up with Simon Atterwell, director of Network Rail Telecom (NRT), to hear of the progress being made to improve the GSM-R radio system. He also discussed ways in which the rail telecoms network could be used to benefit wider society.

Organisation

NRT is part of Network Rail’s Group Digital Railway organisation and operates across all of the devolved routes. This is because the relatively few telecoms specialists are more effectively deployed across the rail network, and telecoms assets do not fit easily into the geographical layout of the routes. For example, there is a single telecoms network control centre for all of Network Rail, and the mesh network of fibre cables and data routers is best managed as a single, unified network.

The data routed through the fixed telecom and GSM-R networks will underpin and connect all of the digital rail systems. These include the European Train Control System (ETCS), which will allow trains to run closer together and to travel at their best speeds whilst maintaining safe braking distances. Connected Driver Advisory Systems (CDAS) and Automatic Train Operation (ATO) will provide decision support to drivers in the cab, so that they have the information they need at the right time to boost performance and safety, while Traffic Management (TM) will maximise performance as trains flow across the network by optimising the use of existing track.

All of these systems will adapt in real-time via the telecoms network as conditions change to aid rapid recovery.

Simon confirmed that a new top team is now in place, which includes some of the best telecoms specialists available in the industry. The organisation also contains experienced railway telecoms engineers, who understand the twin requirements of safety and performance.

In addition, apprentices and graduates are being developed with the right skills to support the network, both now and in the future.

Security

One of these key skills is cyber security, a subject very important to a data-rich operational network. A specialist telecom security operations team, under the direction of chief information security officer Darren Hepburn, manages the security measures which, as well as logical and physical security, include business continuity, disaster-recovery processes and risk management.

These measures, which include threat detection and vulnerability analysis as well as incident management, are some of the best available and the rail industry has learnt from enterprise networks, and other control system industries, in order to adopt best practice.

The details of the measures must remain confidential, for obvious reasons, but it is a subject that is under constant review and updated as threats develop and change.

GSM-R interference

Phased into service across the rail network between 2007 and 2014, GSM-R is a major achievement, with the renewal of the entire lineside fibre network and the installation of over 2,500 radio masts. The system, which allows drivers to speak securely to signallers and receive broadcast calls in an emergency, is now in daily use to assist the safe operation of the rail network. It has been very well received by both train drivers and signallers alike, and future enhancements to the system will include upgrades to support the rollout of ETCS beyond the rural Cambrian route.

The initial rollout of the GSM-R System led to a number of issues that impacted on operational performance. Some of these were caused by interference from nearby public cellular mobile radio sites and registration issues, such as locations where drivers could not see the information required to register and ‘set up’ the cab radio on the network. These all led to train delay incidents, so Project Artemis was formed and, working closely with train operators, it led to a number of initiatives in response to the issues. This included an upgrade of the in-cab radio software and other modifications to radio sites and processes.

The problems included poor visibility of signals at platforms. Quite often, due to the varying length of trains, drivers could not see the relevant signal number and had been either relying on pocket reminders, memory or using a ‘wildcard’ system to register the in-cab radios. In some locations, new small blue and white signs have been provided on platforms, to advise of the signal number ahead.

Other locations suffered from short-term interference from nearby public mobile operator radio masts. It was found that cab radios affected by the interference did not automatically regain the GSM-R network when the interference subsided, and were left in a state displaying “Searching for Networks” on the driver’s control panel. This was particularly common for radios in the rear cab of a train, being discovered when the service terminated and the driver changed ends for the return journey. A process has been developed to recover the radio by the driver simply keying in a reset procedure.

GSM-R registrations were also failing due, in part, to the in-cab radios attaching to an incorrect radio cell. These registration rejections were resolved by a reduction of the transmitted radio power from the interfering public mobile network operators’ sites, along with physical changes to the serving GSM-R mast antenna orientation and modifications to the configurable parameters of the radio site.

The Artemis project has been a great success and routes have reported a dramatic improvement in performance, with far fewer train delay incidents caused by GSM-R registration failures.

Improving telecoms for society

Over the years, there have always been various proposals to sell off and commercialise the railway telecoms assets. Fundamentally, though, the assets are there to support the safe and secure operational requirements of the railway, and Simon was clear that ownership, control and management of the network will remain with Network Rail. However, his team are involved with a number of trials to support telecoms services outside of the operational arena.

In issue 151 (May 2017), Rail Engineer reported on the Government’s Digital Strategy for the UK. This strategy included the comment that publicly owned or funded networks, such as the Network Rail telecoms network, offer the potential to increase fibre connectivity. As a result, these would be investigated to see how they could be opened up to provide vital ‘backhaul’ infrastructure, which could help to increase business and residential connectivity in hard-to-reach areas. They might also provide connections for the emergency services network (ESN), which will provide the next generation integrated critical voice and broadband data services for the three emergency services (police, fire and rescue, and ambulance) and other public safety users.

This is now starting to happen and NRT is involved in a trial with Broadband Delivery UK (BDUK), part of the Department for Digital, Culture, Media & Sport, in delivering superfast broadband to rural areas of Cumbria using the railway fibre network. A trial is also underway to provide services for ESN in such locations as the Severn Tunnel.

It is important that any connections to other networks are made safely and with no interference or capacity implications to the operational railway, which is why NRT has to be involved whenever a third-party telecoms operator connects to, or operates on, the rail network.

NRT is also involved in assisting mobile network operators to tackle public radio ‘not spots’, where there is poor coverage near to the railway. The plan is to provide cellular mobile operators with the ability to access and connect to ‘neutral host capability’ radio sites on Network Rail land. This will help to remove poor coverage areas for rail customers, lineside neighbours and rail maintenance teams, together with improving Wi-Fi access on trains where this is provided via public cellular radio systems.

The interference that has been experienced by GSM-R from third-party sites can be managed better with NRT being able to influence the design with filtering and antenna configuration, and it also allows the NRT engineers to gain experience with 4G radio, which is likely to be used for the next generation of rail radio to replace GSM-R, unless the industry waits for the introduction of 5G in a few years’ time.

Another scheme to improve Wi-Fi on trains is the Project SWIFT (Superfast Wi-Fi For Trains) trial, currently taking place on the Edinburgh-Glasgow route. The pilot scheme is being funded by Innovate UK and RSSB and is being undertaken on behalf of the entire rail industry. It is aimed at fully understanding how today’s on-train Wi-Fi can be taken to the next level.

This proof-of-concept trial is being delivered to ScotRail. Cisco is leading the trial using Fluidmesh technology and NRT is providing the backhaul links. The Edinburgh-Glasgow route is typical of the UK rail network in terms of current mobile coverage. Cellular mobile networks provide good connections in the two main cities and within the confines of the towns that the rail route runs through. However, coverage becomes patchy as the trains cross open country or are in deep cuttings along the 79km route.

The project will use the trackside NRT fibre to backhaul data from the existing trackside GSM-R infrastructure and newly installed infill masts. The masts will access the unlicensed 5GHz Wi-Fi spectrum to connect trains to the NRT fibre network. Indications are that an average 350Mbps, with peaks at 500Mbps, may be achieved with seamless handover between the radio sites, and with no packet loss during the handover.

The not-for-profit structure of Network Rail allows NRT to provide the backhaul connections required for the innovative schemes at cost, maximising the benefit to society.

These interesting trials, along with other NRT innovations, will be covered in more detail in future editions of Rail Engineer.

This article was written by Paul Darlington.


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