FRMCS is slowly becoming a well-known acronym among people associated with the railway. It stands for Future Railway Mobile Communication System which, in broad terms, means Track to Train radio. The present system – GSM-R – has been around since the mid 1990s and has been a huge success.
As a former British Rail radio engineer, your writer can claim to have had a small part in selecting GSM as the technology standard for railway radio across Europe and beyond. In the UK, GSM-R replaced the former Cab Secure and National Radio Network systems and, in addition to providing voice communication between train crew and operating centres, it was adopted as the bearer for ETCS signalling in the few areas where that had been deployed.
The decision to design and implement GSM-R was made in the early 1990s after which it took Network Rail from 2007 to 2014 to deploy the full system.
So, what is the problem? By its very date of design, GSM-R is 2G technology. In other words – the mobile radio technology that replaced the former analogue phones and began the mobile revolution. Since then, the technology has advanced through 3G, 4G, into 5G, with even 6G in the feasibility stage.
All these advances have improved the availability of bandwidth, data handling capability, security protection from external interference, penetration of coverage, together with the reduction in phone size and access to the internet. 2G is an outdated technology but sticking with GSM-R has saved the railway considerable expense and system disruption by not updating to the future generations of mobile network design along the way. However, there is however a limit to how far this can continue.
Your writer has been advocating for well over a decade that the railway needs to seriously consider GSM-R obsolescence, but there has been a reluctance to move forward at the required pace. Railway management, in particular, has a mindset that radio connectivity will always be there, much as water in the tap or power at the socket. The reality is very different, and a future radio network is needed to provide the safety and operational requirements to fulfil the vision of a ‘digital railway’.
The emergence of FRMCS
Around 2015, it began to be recognised that GSM-R cannot go on for ever and that a new international standard for track to train radio must be developed. Various debates began to consider whether this should be 4G, which had by then started to deploy in the public mobile networks, or whether it should wait for the vision of 5G to emerge. After further lengthy deliberations, the latter was finally selected. This was sensible as 5G has, over time, become the new de facto standard.
Since then, development of the requirements has slowly taken place under the control of a group called European Radio Implementation Group (ERIG) that exists within the Union Internationale Chemins de Fer (UIC) which has its headquarters in Paris. The development of FRMCS will be European led, the net result being a common specification across Europe and for many other parts of the world.
Achieving all of this will be both a technical challenge and a logistics nightmare. The technical aspects will be to produce a specification that meets all foreseen demand. The logistics will be in changing over from GSM-R and maintaining a reliable operational service for all train fleets during the process.
The Great Britain perspective
Along with other countries, Britain needs FRMCS to offer many more services and applications than are available within GSM-R. In order of priority these are:
A bearer for train control systems, principally ETCS, with sufficient capacity to allow multiple trains to be connected in dense traffic areas. The radio must also provide a secure speech path between signalling centres and train drivers including emergency calls, priority call provision and group calls to all trains in an area. This replicates what GSM-R already provides mainly through the adoption of packet switching but the present capability may be inadequate to connect all trains once ETCS is deployed in greater quantities. The data handling requirement for ETCS is not great but it must be guaranteed continuous throughout a train’s journey.
Communication for a train’s business and information needs. This will include updates to any onboard passenger information displays, connectivity to train crew for requests, rostering, unscheduled station stop or route changes, policing situations, train condition monitoring, and such like.
Improved connectivity for passenger communication. The limitations of onboard WiFi are documented. It may be possible with OFCOM agreement to use FRMCS to enhance the service offering but this will also need bandwidth considerations. While some may question the need for this, it is a fact that people increasingly rely on data to communicate with one another.
With these requirements set out, the next step is to turn these into an operational and a technical specification. To achieve this, a series of preliminary trials under the banner name of MORANE 2 will take place over a 13-month period ending in September 2027 which, assuming a successful outcome, will result in Version 1 of the specification. Although the supply industry will be involved in the trials, design and manufacturing may not happen until after this date.
The obsolescence problem
As has been noted, GSM-R is reaching the end of its life, and the present suppliers have stated they are only prepared to guarantee technical support and equipment supply until 2030. Readers will realise by now that it is going to take a lot longer than five years to deploy an FRMCS network. It is therefore essential that GSM-R remains operational for much longer than this date. The solution will be to pay the key suppliers sufficient sums of money to train and retain engineers with GSM-R expertise, and to ensure a supply of spare parts. Negotiations are already taking place for this to happen, with some countries looking to extend the date to 2035 but with others looking towards 2040. To put this into perspective, the UK and France have around 16,000 route kilometres, whereas Germany has 33,000. In Great Britain, the main infrastructure supplier is Kontron (formerly Kapsch).
It cannot be emphasised more strongly that having a robust radio connection between track and train is vital to modern day train operation, so these negotiations have to succeed.
New radio spectrum
It took considerable negotiating over a period of time for GSM-R to obtain a 4MHZ chunk of bandwidth in both the uplink and downlink directions for railway use across Europe, namely 876-880MHz and 921-925MHz. Radio spectrum is valuable and considerable technical and economic arguments are necessary to convince the licensing authorities that a dedicated band of frequencies should be granted for specific customers.
For FRMCS, initial thoughts were that the new system could be superimposed on to the GSM-R allocation but, having looked more deeply at the requirements, this is deemed impractical and thus a new set of frequencies will be needed, especially as the dual operation of FRMCS and GSM-R will be required for several years.
Negotiations are well advanced for the use of spectrum in the 1900-1910MHz band to be made available across Europe. The GSM-R bands may be reused to enhance FRMCS services once GSM-R is finally switched off. In Great Britain, discussions with OFCOM are progressing and a positive view is emerging on using the 1,900MHz band.
Radio propagation
There are two fundamentals for radio networks: the higher the frequencies, the greater is the attenuation, and the higher the aerial, the better the coverage. Both present challenges for FRMCS and they are linked. Permitted development rules dating from the 1970s allowed British Rail to erect 100-foot aerial masts on railway land without the need for planning permission. This facility still exists although the 100 foot is now modified to 30 metres. However, erecting masts is always controversial and near neighbours can get very upset if a 30-metre mast suddenly appears close to their property. With this in mind, Network Rail is expected to limit new masts to a height of 15 metres, which will impact on the potential radio coverage from such sites.
Using the 1,900MHz band means higher attenuation, so the coverage from any aerial transmitter site will be reduced. Initial estimates indicate that an additional 3,000 masts will be required over and above the GSM-R masts that already exist, to provide FRMCS throughout Great Britain. In dense railway areas, this may be fortuitous since the 5G cells will be smaller and thus more radio traffic can be handled. Out into the rural areas, the need for small cells is less obvious and one way to reduce the cost of FRMCS coverage will be to rent aerial space on masts / towers owned by third parties such as water, electricity, or mobile network operator companies. It will be very much a situation of ‘horses for courses’.
Private or shared networking
The current thinking is that FRMCS will be a private radio network wholly owned and operated by the Rail Infrastructure companies, which for Britain is Network Rail but soon to be Great British Railways (GBR). This is commensurate with GSM-R and previous radio networks that have provided track to train communication. There is a feel-good factor in this thinking in that it gives the railway full control over the network operation and its security. It does however come at a price and there will likely be pressure for the railway to share its future radio network either in full or in part with other industries that provide safety or security services within their radio operation.
In essence this would be by the provision of a Virtual Private Network (VPN) for which the railway would have full control but have to share much of the radio infrastructure with a third party. The Emergency Services (police, fire and ambulance) are a typical example. Their current AirWave networks will be requiring renewal and current plans are to move these to a 4G LTE operation, though 5G might yet emerge as an option. The thoughts of moving it all to a ‘cloud based’ operation have surfaced but any such ideas will need to be aligned to the requirements of the functional and technical specification.
Connecting it together
A national network demands massive connectivity. As part of the GSM-R project, British Rail and then Network Rail had to invest in expanding its network of fibre optic cables and digital transmission. This had started as a roll out in the late 1980s and early 1990s to replace the co-ax cables and analogue systems established in the 1960s. The technology known as Synchronous Digital Hierarchy (SDH) enabled vital bandwidth to be made available to virtually all the radio sites as GSM-R was being built and commissioned. The transmission network branded as Fixed Telecom Network (FTN) was resilient in that, should a failure or cable cut happen, the radio control instructions and traffic could be routed another way.
Since those days, both the radio and transmission technology have moved on and the current provider of the railway transmission network – previously known as Network Rail Telecoms but now renamed Digital Data & Technology (DDAT) – has introduced a new network known as FTNx which is based on Internet Protocol (IP) which permits improved accessibility to data systems and thus more flexibility of use. FRMCS will make use of this network and every radio infrastructure element will have an IP address.
Train mobile implications
In 2019, Rail Engineer reported on the contract to supply new V4 train mobile radios across the entire fleet of locomotive, multiple units, and yellow plant, a total of around 9,000 cabs. These had been designed by Siemens Mobility at its Poole premises and would be supplied over a five-year period. To ensure maximum return on the investment, each cab radio was fitted with an expansion card that provides increased functionality by adding GPS, 4G WiFi, and an accelerometer. This also ensured that the train has a GSM-R cab radio that can enable the transition towards FRMCS.
The radios are identical in terms of space envelope, screen display, power supply, and aerial connection to the preceding mobiles and thus changeover from old to new could be carried out at depots in the minimum of time. The project had a value of £55 million and is now complete. The performance of the sets has overcome the emerging difficulties with unwanted interference. The previous V3 radios were returned to Siemens for modification to the new design, thus saving considerable expenditure into the future.
Information received recently from Steve Parsons, the business development lead for Mobile Communications at Siemens Mobility, confirms that the 4G networking has been fully tested and has been deployed for train borne condition monitoring on the South West Railway infrastructure. This innovative solution, utilising the technology already deployed within the cab radio, links the GPS and vibration data which can be processed within the radio to identify any track degradation.
With FRMCS being capable of deployment across either a public or private network, Siemens is a key stakeholder within the Morane 2 project, which will test all associated equipment both in the laboratory and field environments, and in turn will impact on the final version 3 of the FRMCS specification. Information from Siemens is that the V4 radio can be adapted to use the 1,900MHz band by changing out the 4G LTE module for whenever the FRMCS specification is finalised. This will require both software and hardware components to be designed but with the continuing capability of providing GSM-R operation in the 900MHz band while both radio networks have to work concurrently.
The hopeful news is that the existing cab radios will be replaced with new ones and then sent back to Siemens for the upgrade as much has already been achieved when upgrading from V3 to V4. A stock of radios can thus be created as the changeover to FRMCS is progressed.
Much will depend on the changeover strategy that is decided by Network Rail or GBR. It is expected that the means of changeover will be by having the trains able to operate on both FRMCS and GSM-R as the infrastructure is changed to FRMCS.
Clearly, the situation with providing train equipment with a FRMCS capability will be a major factor under the banner of Train On Board Equipment (TOBE), fitting is planned to start in 2029.
The predicted cost and timescale
This project is going to be huge. The amount of new infrastructure or modifications to the existing radio infrastructure will require considerable investment, and an initial estimate of at least £2 billion has been calculated. A centralised radio planning, engineering, and implementation team, coupled with local resources to undertake the necessary connectivity, will be essential if the project is to proceed in the most efficient manner.
While the investment required will raise eyebrows, it will be spread out over a period of time. Establishing the principles and commencement of survey work has budget provision in Control Period 7 (CP7) but with the bulk of the implementation activities being spent in CP8 which begins in 2029. Paying to keep supplier support of GSM-R active into the 2030s, particularly the retention of people skills, could be significant.
The implications for the train borne equipment, as has been mentioned, affects not just the cab radios but also the train radio to support ETCS operation. This is an unknown but is likely to add to the overall cost burden.
This project is not one that can be regarded as ‘nice to have’ – it is absolutely essential as the radio connection is vital for so many applications. The Department for Transport is aware of the situation and knows that funding must be made available. The pressures will be on to keep this to a minimum which will demand the maximum pragmatism in both the architecture of the new network and the work of the implementation team.
We all await the emerging plans with a watchful eye.
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