Critical comms for public transport: at the crossroads

Philip Mason talks to Transport for London and Brussels STIB about how recent, major, public safety/health incidents have informed their critical communications strategies.

As regular readers of CCT will remember, in the last issue we published a feature focusing on Motorola Solutions’ work with Polish energy distributor Energa-Operator.

That article was prompted, at least in part, by the project winning the award for best utilities roll-out at the most recent ICCAs, taking place online at last year’s inaugural Critical Communications Week. The more we dug into the Energa TETRA roll-out, the more fascinated we became by it, not least due to the sheer size of the project, as well as the level of co-ordination involved in its successful completion.

With that in mind, we are following up by focusing on another 2020 ICCA award winner, this time situated in the transport space. The project in question is also eye-catching in its scale, covering as it does the whole of London. It is the speed of roll-out which is truly impressive, however, with Transport for London (TfL) having to rapidly expand its comms capability at the height of the Coronavirus pandemic.

Space in the place

Prompted by COVID-19, the TfL project was an attempt to provide radio communications to cover a number of extra buses, laid on in order to help passengers in the UK capital to socially distance. It involved collaboration between the aforementioned public transport provider and Tait, with the latter supplying Push-to-talk over Cellular (PoC) capability, fully integrated into its already-rolled-out DMR Tier III network.

Giving an overview of the COVID-19 project, a statement from Tait released at the time said: “TfL has used [PoC] integration in daily operations taking place throughout the crisis. When it needed to add more buses to its fleet, TfL and Tait worked together to quickly modify the TeamPTT solution to make it suitable for use by the external bus drivers.

“The whole project came together in less than four weeks. We created a scalable radio service to enable up to 80 buses to be added to TfL’s PoC service, providing communications – as well as an emergency link – to its Network Management Control Centre [NMCC].”

Thomas Brewster is Transport for London’s service delivery manager for surface transport technology and data, putting him directly at the centre of the project. Going into detail about its background – while also providing some context regarding TfL’s overall comms network – he says: “The original roll-out of the Tait PoC service dates back to January 2020, which was obviously prior to the Coronavirus pandemic.

“We had around 200 users at the point when COVID-19 hit, primarily rolled out to what’s known as our ‘street users’. These are the people who stand at particularly busy interchanges, relaying information back to the control centre about what’s happening on the roads and at our bus stations.

“Users of the Tait PTT technology have the ability to talk amongst themselves using the cloud, and over DMR Tier III via common cellular devices. The latter is enabled through a Tait communications app.”

According to an audit carried out by TfL in March last year, the company had a fleet of just over 9,100 buses at its disposal, contracted from 13 separate operating companies. These ran over 700 different routes across the city every day, covering everywhere from Croydon to Colindale.

The situation grew more complicated, however, with the onset of the COVID-19 pandemic in early spring of last year, a situation which immediately ushered in the need to establish a variety of measures to help keep passengers apart.

In the first instance, these took place on the buses themselves, for example through banning the use of adjacent seats. At the same time, meanwhile, TfL also attempted to make buses less crowded by putting on more services at particularly busy times. The most obvious example of this was during the time of the day known as ‘the school run’, and it was the work in this area for which it won the ICCA.

Going into greater detail, Brewster says: “TfL was asked by the Department for Transport to provide additional capacity on our designated school routes, which are always numbered in the ‘600s’.

This designation doesn’t mean that another passenger can’t get on, but from a service perspective we’ll run a particular trip twice a day, specifically for the benefit of children traveling to and from school.”

He continues: “The first thing we had to do – obviously – was provide the buses, which we accomplished through approaching bus companies that we could contract with. They came from all over the country.

“At the same time, we had to provide some kind of comms solution for the vehicles, which frankly – because they weren’t TfL stock – could have been anything. That provided its own unique set of potential problems, particularly in terms of things like fit-out, as well as training of the drivers.

“We didn’t know when the buses were going to arrive with us, or what we would be able to install in the cab. There were also no specifics when it came to the type of smartphones the external drivers would be using, with each bringing devices issued by their own separate organisations.”

According to Brewster, there were two key criteria for communications roll-out in the new vehicles. The first was that devices – whatever form they ultimately took – had to be “vehicle agnostic”, while leaving as small a ‘footprint’ as possible. The second, meanwhile, was that use didn’t require drivers to break the law, in particular UK regulations forbidding drivers from using handhelds while behind the wheel.

“We had a very intense planning session over the course of about five days,” says Brewster. “Arguably the biggest issue was figuring out how PTT could be achieved without actually picking up the device.

“We solved this through the use of wearable, remote speaker mics – linked to the smartphone by Bluetooth – operated by touching one of three buttons. The smart device itself sits within a mounted cradle, attached to a high-pressure suction cup, in an area of the cab where the driver could not handle it while operating the vehicle.

“At the same time, we also needed to make sure that the speaker was loud enough, and that the driver could be heard over any noise that might be coming from the vehicle or the passengers. The set-up enables them to communicate with both garage control and, in the event of an emergency, the TfL Network Management Control Centre.”

It is clear from talking to Brewster how innovative – not to say unique – he believes the TfL roll-out to be. This is despite the increasing use of PoC technology across any number of different verticals, something that he freely acknowledges.

One reason for this belief is the way the solution leverages TfL’s pre-existing DMR Tier III network, thereby enabling pretty much instant access to a variety of system-wide configured talk groups. Another reason is its provision of asset tracking via nothing more complicated or bespoke than the device’s own internal location technology.

Drilling down further into the voice functionality, Brewster says: “The set-up is entirely predicated on group calls. One-to-one is possible, but drivers are prevented from doing that via a ‘kiosk’ mode. At the other end, the garage uses Sonim XP8 ruggedised handsets, and if a driver initiates communication, all of those users are dragged into a single talk group. Anyone at garage control can then respond to the driver.

“The third button on the radio mic initiates an emergency call through to our Network Management Control Centre. The NMCC operators each have a tablet-view of where the buses are, as well as also having access to the Tait Comms smartphone app so they can communicate with the driver.”

Going it alone

The TfL PoC roll-out demonstrates just what can be achieved through effective collaboration and co-ordination, no matter how difficult the circumstances. By way of a contrast, our next deployment, which likewise coincided with a crisis situation, illustrates the possibilities when an organisation demonstrates the will to blaze a trail
on its own.

Frederic Jans-Cooremans is project and radio spectrum manager for Brussels-based public transport operator STIB. He has spent several years working on what the organisation claims is the largest private TETRA network in Belgium, developed to be an independent means of communication for the whole company. As fate would have it, the tender for this went out just a few months prior to the 2016 Brussels terrorist attacks.

Taking place across the city, the attacks took the form of three co-ordinated suicide bombings, all of which targeted its transportation network. The last of these took place at Maalbeek metro station at the height of rush hour, with the first two bombs being detonated around an hour earlier at Brussels Airport. Thirty-two people were killed, not including the three bombers, while more than 300 were injured.

As might be imagined, the bombings plunged the city into something approaching a state of chaos, not least when it came to the transport system, large sections of which were temporarily suspended. According to Jans-Cooremans, however, events immediately following the attacks had also made it increasingly difficult to communicate using digital equipment. This included not only commercial smart devices, but also the Belgian emergency services’ TETRA network, ASTRID.

Discussing the fall-out from the attacks, he says: “I remember that day very well, partly because of the massive impact it had on people’s lives and routine. From my window at work, I could see a huge queue of people stretching in front of the central station, due to screening by the military. The situation was an incredible mess.

“From STIB’s perspective, the first thing to get back up and running was the buses, something which took place the day after the bombings. The tram was two or three days later, but only on the surface, rather than portions of it which go underground. The Metro line regained full service about two weeks after, but people were very nervous about using it.”

Moving onto STIB’s communications capabilities, he continues: “At the time, we shared – and currently still share – the Belgian emergency services TETRA network for things like the Metro. At points during the day, we were finding that it simply didn’t work that well, with calls made by our personnel being shut down after something like 10 seconds.

“One reason for this was that the network had been suddenly flooded with emergency services users from all over the country, called in via mutual aid. This led to some base stations reaching full capacity, something which had an obvious knock-on effect.

“At the same time, all of these emergency users – quite naturally – possessed higher priority than we did when it came to the use of ASTRID. I think it’s important to state that at no point did the network suffer an outage, simply that the volume of communication taking place was unprecedented.

“Our trams and buses weren’t affected by any of these issues, possessing as they do their own analogue network. Buses were VHF, while trams operated on UHF.”

Jans-Cooremans began working for STIB in 2009, having previously been with a private radio solutions company. As he tells it, a core ambition even before he moved over was to install private TETRA for Brussels’ public transport, something he started laying the groundwork for almost as soon as he arrived.

Fast-forward to 2014, and after much discussion and preparatory work, the tender for the network finally went out. It was eventually won by Zenitel-SAIT (now Securitas), which set about provisioning not only the Brussels Metro but also buses and tramways.

Going into greater detail, Jans-Cooremans says: “Ever since I joined the company, my aim was to initiate a TETRA network, distinct from ASTRID. I’d actually had that idea years before, when STIB was one of our customers. There’s STIB optical fibre almost everywhere along the tracks in Brussels, so I always wondered why the transport system didn’t have it.

“Before the tender went out, I was constantly putting the question of what if there’s a big problem with the shared network. I was not alone in saying that, and the events of 2016 – and the study that followed – added a certain amount of extra urgency to the project.”

Regarding the burgeoning STIB network itself, it will cover the whole of the Brussels public transportation system, reaching from the inner city to the suburbs. Leveraging two carriers, and more in the city centre, it operates on 410-420MHz, which is the frequency set aside for Belgian commercial TETRA.

Digging deeper into the roll-out itself, Jans-Cooremans says: “I primarily focus on installation of the outdoor coverage, all of which is now functional. There were a variety of different ideas about installation in regard to buses and tramways, but they’re all procured now.

“In terms of the roll-out itself, the key challenges have taken place in the realm of infrastructure. We’re able to share masts with ASTRID – which is running at 380-390MHz – but there was still the need for new structures in certain regions and on certain buildings. To a degree, public transport is seen as less important than the emergency services, so there was quite a lot of dialogue with the relevant authorities.”

He continues: “The other key environmental issue was in relation to field strengths, in particular regarding the safety of people being a short distance from our base stations and repeaters. We had to conduct simulation studies in order to be sure to be well within the imposed limits.

“We ultimately worked that out by deciding to transmit using very low power, via radiating cables. These are specifically designed for transmission in confined areas, and the impact is very tiny.”

Coming back to the 2016 terror attack, one other vitally important piece of learning, according to Jans-Cooremans, is around radio use itself. While he, quite rightly, has absolutely nothing to say about emergency services’ strategy that day, he is at pains to point out some of the principles ingrained in STIB TETRA users as part of their daily use.

“There are many ways to improve the performance of a network,” he says, “such as increasing the amount of base stations, as well as upping the number of carriers per base station. At the same time, it’s important that users are made to understand how to get more out of their radio, particularly when a large-scale event occurs.

“For instance, one thing we would heavily discourage is the scanning of different talk groups – in fact, we disable that functionality altogether. Use of scanning requires the nearest base station to transfer each of the different talk groups to a single radio, which is a huge waste of capacity. You can understand why a manager would find it useful for monitoring purposes, but it’s not part of our strategy.

“Another tip from the user perspective is simply to keep the PTT button pushed if you’re being kept waiting, rather than ending the call and being pushed out of the queue. We also recommend communication through talk groups rather than one-to-one calls. Again, all this is just basic radio discipline.”

While apparently disparate, the projects discussed in this article have two key things in common. First, they demonstrate just how important effective comms technology is to the running of modern, large-scale, public transport systems. At the same time, they also showcase exactly the sort of innovation becoming increasingly synonymous with the critical communications sector.

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Editorial contact

Philip Mason
Editor, Critical Communications Today
Tel: +44 (0)20 3874 9216