Safe and reliable communications are a critical component in operating modern railway networks. Voice radio, signalling, asset protection, CCTV, station services and alarms form the basis of a typical rail system, with telephony, data and internet connectivity between offices shaping corporate requirements.
In the lead up to AusRAIL 2014, Adam Oliver, Senior Communications Engineer at Calibre Global joined us to shed some light on the challenges of rail deployment and the benefits and limitations of MPLS based networks.
What do you think are the key challenges we face today in rail deployment?
Adam: From a signalling and communications point of view, the biggest challenges we face are caused by the move towards converged networks. When safety critical systems share infrastructure with non-critical services, security and interaction needs to be tightly controlled. Similarly, lack of understanding between the two disciplines and how they interact has the potential to result in sub-standard designs.
From a security point of view, any time critical and non-critical applications share infrastructure, the methods of interaction need to be well understood and highly controlled. As an example, the last thing you want is to inadvertently give access to your systems from the internet. Along the same lines, faults or high bandwidth utilisation in a non-critical application should not be allowed to have any impact on critical services. Either of these situations can impact the safety of passengers or payload, with disastrous results.
In the past, signalling and communications components of a rail deployment have been completely separate, with virtually no interaction between the two disciplines. More recently, signalling and communications are being integrated into an integrated railway network. As engineers, we need to understand the implications of this change from both sides of the fence. Proving that an Ethernet link is running error free, might be sufficient from a communications point of view, but if there are packets dropped that cause the signalling system on the link to flag a track circuit as occupied, then the overall design won’t work. Similarly, a signalling protocol that assumes two signalling devices are directly connected is not necessarily the right solution if the devices use an Ethernet network, in which packets may be delayed or lost.
Without this “big picture” understanding, both the signalling and communications disciplines will continue to run into situations where expectations and requirements are not met. Ultimately, the end result is a sub-standard technical solution where nobody wins. It is crucial that everyone works together to ensure requirements are well understood, to ensure the best possible technical outcome is achieved.
How can a Multi-Protocol Label Switched (MPLS) network help to overcome these challenges?
Adam: An MPLS can help to overcome some of the interaction challenges by providing a flexible, robust network foundation which the various rail applications can utilise. For example, a typical rail network might have TETRA (voice communications), SCADA (site monitoring), rail signalling / asset protection, information services, and a host of other supporting sub-systems. The MPLS core can be tailored to meet the requirements of the application such as available bandwidth, prioritisation of critical services, rapid restoration around faults, and even network topologies can be specified.
More importantly, within the MPLS network each application is effectively isolated from every other application. Hence a fault in one application won’t cause the rest of the applications to experience problems.
Are there any limitations to the MPLS based networks?
Adam: The biggest limitation at the moment, in my opinion, is from a management point of view. MPLS, as a technology, has been around for quite some time – most major communications vendors have a product which will support it. Where MPLS hasn’t quite developed is in the ability to quickly provision a new service using an intuitive graphic user interface. Well-developed technologies such as SDH have systems where you can click two points on a network, and the system will automatically do the hard work as far as creating cross-connections and the associated provisioning. MPLS isn’t quite at that stage yet, although the extensions to the standard are paving the way to making this happen. Until that happens, there is a requirement to have MPLS-trained people designing, implementing and changing the network. I don’t necessarily see this as a bad thing, because ultimately you don’t want to be completely reliant on a software package to design and maintain your network.
The 2014 theme for AusRAIL is “Making Innovation Work”. How important do you think it is to make innovation work in the rail industry?
Adam: Innovation is hugely important. Innovation allows us to continually learn and develop, both ourselves, and the tools we use.
While I don’t advocate change for the sake of change, it is important to always be looking for better ways, new ways, to do things. Innovation is what allows us to take a problem, spin it around and look at it from a new angle and come up with new solutions. It allows us to improve on existing processes and do things better, faster, or cheaper.
Let’s face it, if it wasn’t for innovation, trains would still be steam-powered.
Is there anything else you are looking forward to at this year’s AusRAIL?
Adam: In my opinion, WA has been at the forefront of making innovation work, particularly in heavy haul rail over the last 10 years. At AusRAIL 2014, I’m looking forward to hearing about the innovative solutions that have been adopted on projects. Innovation in the rail industry helps align solutions with the changing needs of our clients and will continue to strengthen our industry.
Adam will be presenting his paper on “MPLS based networks in railway deployments” in the IRSE Stream at AusRAIL 2014, taking place on 11th and 12th November at the Perth Convention and Exhibition Centre. To find out more about the AusRAIL program and to register, please visit the AusRAIL website here.
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