Providing the rail industry with telecommunications services is complex and often misunderstood. The uninitiated think of it as just another commodity that can be bought along with water, gas and electricity.
In reality it is very different to this perception as not only does it cover much more than office telephones and data devices, it is a core service to the operational railway. In short, if the telecom systems fail, the trains stop.
The UK history of rail telecommunications over the past twenty years has been somewhat traumatic. From the earliest days, the railways were permitted to run their own telegraph systems by the then Post Office monopoly because of the operational necessity that these provided. This status quo existed for around 150 years until the Thatcher government sought to liberalise telecoms firstly with the duopoly (BT and Mercury) and latterly to any company that could provide the right credentials.
Under rail privatisation plans, the extensive railway telecom network was formed into a separate grouping – British Rail Telecoms (BRT) – and sold firstly to Racal Electronics and from there to either Global Crossing (now Level 3) for the main networks or to Thales for everything else.
None of these private companies really understood what they were buying and became increasingly nervous when the performance and safety requirements plus some embarrassing failures invoked penalties that questioned the value of the services they now owned.
At the same time, the privatised Train Companies were tempted to acquire telecom services from order- hungry sales people in a myriad of companies intent on cherry-picking the easy bits and ignoring the more important operational comms. The result was communication chaos with ignorance as to who was responsible for what and with serious doubts as to the integrity of the services being supplied.
In parallel, the need to roll out GSM-R as a replacement for the ageing National Radio Network (NRN) and Cab Secure Radio (CSR) and as a bearer for ERTMS was becoming paramount and Network Rail took the brave step in agreeing the investment for a new fibre-based nationwide transmission network, the FTN (Fixed Telecom Network), coupled with the provision of GSM-R infrastructure.
This would largely replicate, in modern form, what had been sold off in the mid 1990s. It was not cheap but has delivered high-bandwidth resilient capacity to virtually the whole of the rail network.
The creation of NRT
Recent changes to de-centralise the Network Rail maintenance and operational structure into Routes did not fit a national telecommunications service, hence the need to create a new organisation – Network Rail Telecoms (NRT) – which was formed in mid 2011. This was reported on at the time in issue 89 (March 2012) when Andy Hudson, the then head of NRT, was interviewed. The vision for the company was to become the national provider of telecom services for the whole of the rail industry.
So how has it progressed in the intervening three years? Rail Engineer went to see Craig Ellis, the head of technology and engineering at NRT’s headquarters in Milton Keynes, to get an update.
NRT has grown to just over 500 staff and now assumes responsibility for all telecommunications assets within Network Rail as well as supplying limited services to the TOCs/FOCs. In addition to the Milton Keynes HQ, it has regional offices at Paddington, York, Edinburgh and Glasgow plus network management centres (NMC) at Stoke and Doncaster, the latter being managed by Catherine Warren. Andy Hudson has since departed from Network Rail and Simon Atterwell, with senior experience in the telecommunications industry, has become the new director. So how does NRT operate and what is its forward vision?
The asset portfolio and operation
At the core of all NRT activities are its networks including FTN and FTNx. This transmission capacity is based around a fibre cable network laid alongside all main and secondary routes and including some remote branch lines. The fibre is capable of carrying vast bandwidth that will support every type of telecommunications application. The fibre architecture has been carefully designed to allow the creation of hundreds of rings that interconnect nationally.
The associated transmission technology borne on the rings at the time of introduction was SDH (Synchronous Digital Hierarchy) capable of yielding high bit rate data streaming structured around a number of STM-16 rings of 2.5Gbit capacity dropping down to STM4 and STM1 (155Mbit) to serve the various railway centres and depots in the country.
Break out points exist at regular intervals so as to permit local circuit connections to be accessed. These operate using PDH (Plesiochronous Digital Hierarchy) technology, it having become the norm for lower order circuits since the introduction of digital transmission systems (PCM) in the 1960s. A 2Mbit bandwidth is a break out capacity that will support a reasonable video application. Sub dividing down to 64kbit is sufficient for a typical voice circuit and many other low speed applications.
The FTN was finally completed nationwide by March 2013 with 823 nodes around the country thus enabling a ‘digital pipe’ to be available for all the many downstream applications.
The telecom assets on Network Rail are many and varied and include:
- Fibre and copper cable backbones – 16,000km and 22,000km respectively and carrying over 200,000 circuits;
- Operational telephones such as SPTs and signalling centre concentrators;
- Level crossing telephone systems;
- Bearers for rail signalling system control distribution including future ETCS;
- Transmission links for the control of the electric traction power supply including the bearers for the forthcoming national SCADA system;
- GSM-R radio – in excess of 2,800 base stations and 55,000 mobile devices;
- The RailNet telephone network (formerly known as the ETD);
- Customer Information Systems including some 35,000 public address loudspeakers plus departure/arrival screens at Network Rail stations as part of SISS (Station Information and Surveillance Services),
- CCTV networks for station management and security – circa 16,000 cameras;
- Data networks to support a multitude of Network Rail-owned and other rail IT applications.
The traditional separation of operational telecoms and business telecoms is now much more difficult to distinguish with many systems being used for both purposes. Outside telecom providers invariably fail to understand this crossover. A classic example is the RailNet service that not only provides a location- orientated emergency call service but also carries the access to electrical control rooms for voice communication messages associated with
isolations and power-off situations. RailNet connections using DPNSS (Digital Private Network Signalling System) links, provided by Level 3, are a leftover from BRT days and its subsequent sale.
NRT has full responsibility for all these systems along with the architecture, design, supply, installation, testing and commissioning of the associated equipment. A pragmatic approach to maintenance and faulting is adopted whereby NRT operates help desks as a first port of call, with many customer problems being resolved simply by talking through the symptoms and giving the necessary advice. It is not realistic to provide first-line faulting at ground level across the country with its own staff and thus technicians from the S&T areas are used for this task by mutual agreement.
For more difficult faults that require specialist expertise, NRT will despatch its own people, this being termed second-line maintenance. Third- line support, normally associated with the repair/ resolution of equipment, is either performed by a small, bespoke team in the NMC or sent out to vendor partners with some in-house reference networks available to them. Increasing reliance on remote monitoring and diagnostics is the order of the day with the NMCs being able to re- route traffic so as to maintain connectivity in all but the most catastrophic circumstances.
NRT does not just serve Network Rail since TOCs, FOCs and ROSCOs also use its services. Whilst such organisations will generally us public telecom providers for their commercial interface to the customer base, the railway has by necessity become a single entity when it comes to the running of trains. NRT therefore extends its RailNet telephone service and transmission facilities to these companies such that control rooms, signalling centres, depots and stations are all connected by a single network. This facilitates maximum co-operation for day-to-day running and especially during periods of disruption.
FTNx
With SDH being a waning technology, it was only a matter of time before plans were emerging to create an IP-based national network. This, in part, follows the trend of most other telecom network companies but fits very well with the declared intention of Network Rail to move to ‘The Digital Railway’.
FTNx is not just a proposal, it is a reality. Pioneered by NRT up in Scotland, issue 119 (September 2014) included an article on the first FTNx rings to be commissioned in support of the Edinburgh – Glasgow resignalling project (EGIP) and other associated schemes in the area. This employed a 10Gbit access layer with 20 router nodes such that access to VoIP telephones and remote control of interlockings could be achieved.
NRT has now built a core FTNx network centred around a number of 100Gbit IP rings, the main elements of which were in place by October 2014. The creation of intermediate 10Gbit multiples to get to the existing lower- order SDH nodal points is ongoing within the CP5 programmes.
FTNx uses IP/MPLS (Multi Protocol Label Switching) technology running over DWDM (Dense Wavelength Division Multiplexing) fibre application and has a core of 52 nodes, sited primarily at the main railway centres and from where lower-order connections can be made.
As with all IP networks, addressing has to be carefully controlled and NRT has its own address group in IPv4 with provision for this to encompass IPv6 in due course. The design of the network has been entrusted to Infinera primarily for the optical elements and Cisco for the IP elements, both of whom are market leaders in the application of this technology. The potential capacity of data on a pair of fibres is mind blowing: around 80 x 100Gbits!
Safety and security
Although NRT is heavily involved with the supply of communications for the operational railway, it has wisely decided not to enter the SIL jungle (Safety Integrity Level). This does not mean that the impact of NRT service provision is entirely without safety implications, indeed many of the circuits / facilities provided are safety related and some might even be judged safety critical. The provision of SPTs and GSM-R may well be the only means of moving trains when the signals are at red.
The use of IP technology and networks to connect up the elements of a rail signalling system is increasing all the time and in some European countries (for example in Germany), IP object controllers are now located adjacent to signal heads and point machines such that an IP command changes the status of the trackside device.
It is only a matter of time before such networking becomes commonplace everywhere. This demands a high level of safety competence in the telecom provider and the network has to be designed from the outset to include safety considerations. It often includes the preparation of a safety case and NRT has the in house expertise to do this, aided on occasions by external safety verifiers such as Ricardo Rail for an independent assessment.
Security is of equal importance and a proactive management approach to network protection is taken. Firewalls and operational support systems are in place with the two NMCs being duplicates of each other such that the failure of one site will not result in a loss of control. Cyber security is a concern for many parts of Network Rail, and NRT’s involvement in the co-ordinated approach is headed up by Darren Hepburn, the chief information security officer.
Future prospects and aims
From the foregoing, it must be obvious that NRT is an essential part of Network Rail and key to the running of a successful train service. BR and other railways (notably Germany) have tested the feasibility of outsourcing the telecom operation and have had to back pedal quickly.
There is a growing dependence on the FTN and FTNx for the distribution of critical information for rail signalling and electrification control, and this will mean a higher status on the safety ladder.
However, it does not mean that NRT is lacking imagination to improve communications facilities on the railway so as to take advantage of current day social media technology.
A typical example might be level crossing safety, which in the future could be further advanced by enhanced warnings to smartphones that provide the status of level crossings in the mobile coverage area, such that any pedestrian, cyclist or motorist approaching a crossing would be alerted to oncoming trains and warned accordingly.
Similar technology could well aid the protection of trackside workers and the R&D group within NRT is looking at exciting opportunities around fibre sensing, cyber security analytics and a connected railway, running over a next-generation network.
NRT must be wished well with its endeavours since they are intrinsic to the railway.
IP design for FTNx
NRT chose Cisco, via its partner Telefónica, to design and deliver FTNx. The use of commercial, off-the-shelf products (COTS) is creating a standards- based, IP MPLS network capable of delivering reliable mission-critical, operational and commercial services.
As part of the Cisco Connected Rail solution, Cisco ASR 9922 routers, distributed throughout the country, provide core routing functions, while the distribution layer of the network relies on ASR 9010 series routers. Meanwhile, Cisco ASR 903 routers manage local, point-of-presence (POP) connectivity in hundreds of REBs alongside the tracks.
All products comply with relevant railway standards and the network design meets the requirements necessary to connect interlockings and handle both traffic management communications
and SCADA for electrification. The network also currently transmits lineside telephony.
With the capacity to support future services, FTNx can deliver commercial telecoms into stations, connect to sensors that monitor Network Rail assets, and provide backhaul train-to-wayside communications in areas where 3G/LTE coverage is insufficient.
