Smart Metros Demand Smart Telecom Networks
From mission-critical WANs to OT cloud and AI, metro operators’ digital ambitions depend on resilient telecoms that ensure security, scalability and performance, writes Benoît Leridon, Nokia’s Network Infrastructure Transportation Market Leader.
www.nokia.com
Rising passenger volumes are transforming metro networks into denser, more dynamic systems – with more trains, busier stations, and increasing safety and security challenges. To stay ahead, operators are turning to digital solutions that safeguard assets and protect passengers.
Digitalisation also helps ensure a metro system’s reliability and improve its efficiency, through monitoring that supports predictive maintenance and automation that can optimise operations. An increasing number of metro operators are embracing digital transformation, but one essential thread underpins every initiative – connectivity.
A smart metro depends on sensors to collect critical data, which must be transmitted and analysed in real time. Achieving this requires seamless communication between tracks, trains and stations. Telecom networks form the backbone of digitalisation, so any digital transformation initiative can only succeed if operators first establish reliable, high-performance communications.
Mission-Critical WAN
At the heart of a digital metro is a mission-critical wide area network (WAN). Unlike legacy networks, today’s IP/MPLS-based multi-service WANs provide the security, performance, and resilience needed to support a wide range of applications simultaneously.
The benefits are clear: high bandwidth that feels almost unlimited compared to the past, quality of service tailored to the needs of each service, and the flexibility to adapt to both legacy and new applications. Whether it’s signalling, communication-based train control (CBTC), video surveillance or passenger information, each system has its own operational requirements, and the network can now be designed to meet them precisely.
Segment routing is becoming the de facto standard in IP networks. By reducing protocol complexity, it simplifies operations and makes scaling possible even in networks with hundreds of nodes. Ethernet virtual private networks (EVPNs) add another layer of efficiency and redundancy, providing reliable Layer 2 services essential for applications such as CBTC.
Finally, traffic engineering ensures resilience for safety-critical systems. Using the ‘blue/red’ redundancy model, data can be routed along separate paths so that even if a node or link fails, both channels are never affected at the same time. This combination of bandwidth, availability, flexibility and advanced tools makes the WAN the backbone of any successful digital metro.
Extending into the OT Cloud
If the mission-critical WAN forms the backbone of digital rail, the operational technology (OT) cloud is the next layer, bringing the same reliability, flexibility and resilience into the data centre.
Typically a private cloud, it’s most often on-premise, but sometimes can be hosted in a dedicated data centre, purpose-built for rail operations. While CBTC will continue to run on its own dedicated servers due to safety and certification requirements, the OT cloud delivers clear advantages for a wide range of other applications.
Systems such as SCADA, CCTV and passenger information can be hosted more efficiently by pooling compute, storage and memory resources. This approach embeds redundancy, improves resource use, and enables smoother upgrade cycles through microservices, helping operators adapt faster to evolving needs without compromising reliability.
Integration with the mission-critical WAN is essential. Extending connectivity from the IP/MPLS backbone into the OT cloud ensures end-to-end performance, consistent redundancy and quality of service across the entire system. In this way, the OT cloud isn’t a separate entity but a natural extension of the multi-service network.
Security Foundations
As digital rail extends into the OT cloud, security becomes even more critical. Every new application and connection increases the attack surface, making the network itself both a potential target and the first line of defence. A zero-trust approach is essential: authenticating devices as they connect, adapting network behaviour accordingly and limiting the damage any unauthorised access can cause. This enables the network to not only blocks attacks but also minimise their impact.
Layered protections add resilience. Complementary to the network defense, Threat Management Systems and Intrusion Detection Systems can monitor traffic, detect anomalies and ensure that devices run up-to-date firmware. These measures reinforce application-level security, protecting against increasingly sophisticated cyberattacks.
Compliance requirements such as the Network and Information Security Directive 2 (NIS2) and International Electrotechnical Commission (IEC) standards are accelerating this shift, embedding security into the WAN and OT cloud from the outset. Looking ahead, the rise of quantum computing adds further urgency, as many traditional encryption implementations will eventually be vulnerable. A multilayer, defence-in-depth strategy, combined with quantum-safe encryption, will be vital to safeguard future metro networks.
AI in Metro Operations
With robust defences in place, attention is turning to how the same digital foundations can unlock new forms of intelligence, most notably through the application of artificial intelligence (AI).
The most common application today is video analytics, where algorithms detect anomalies such as abandoned bags or passengers moving against the flow. This technology has driven rapid expansion in surveillance: where stations once deployed 20 cameras, many now operate closer to 200.
Beyond surveillance, rail operators are turning to predictive maintenance. By analysing data from dense networks of sensors, AI can identify issues before they cause failures. Some operators are already experimenting with ‘health check points’ in tunnels and stations, where trains pass through clusters of sensors that monitor multiple conditions simultaneously.
Nokia’s Role in Smart Metros
Nokia is an enabler of smart metros, providing the connectivity that supports everything from on-board systems to trackside equipment and station applications. Its partnerships with major signalling vendors add further credibility, ensuring networks meet the latest requirements for mission-critical urban transport systems.
The company has extensive experience in both greenfield and brownfield environments. The Grand Paris Metro offers a standout greenfield reference: four new lines built with 100-gigabit capacity, segment routing, EVPNs and extensive CCTV, creating one of the most advanced metro communications backbones in the world.
At the same time, large-scale brownfield migrations at ‘Autonomous Management of Parisian Transportation’ (RATP) and Transport for London (TfL), demonstrate Nokia’s ability to modernise legacy networks. These complex projects required carefully designed migration strategies that minimised risk while transitioning to modern IP/MPLS.
Without resilient communications, the vision of a smart metro cannot be realised. The path forward is clear: IP/MPLS with segment routing provides the proven framework to deliver today’s applications while adapting to future demands. Telecoms aren’t just an enabler – they’re the cornerstone of the smart metro journey, so don’t overlook them.
www.nokia.com
