How TS 50701 secures the entire railway infrastructure

As part of the Cybersecurity Awareness Month, we are doing a deep dive into OT security strategy and measures for various critical infrastructure sectors. Today we will examine cybersecurity measures that we recommend for railway companies. Any discussion on railway security is incomplete without referring to the CENELEC TS 50701 standard so we will be doing a deep dive on that as well.

Today’s railway systems have to deal with multiple security challenges. The attack surface has expanded from the ticket office to the locomotive itself and the sensor clusters. A cyberattack is no longer just an IT problem; it's a critical safety risk. Even on a good day, for railway companies, securing this complex, interconnected environment is a monumental task.

This is usually where the CENELEC TS 50701 standard makes its entrance.

It's not just another standard. It is in fact the first comprehensive framework designed by railway experts for the railway sector, providing a complete, end-to-end (E2E) lifecycle approach to cybersecurity.

For railway operators and asset owners, understanding TS 50701 isn't optional. Instead it is the foundation of a resilient and secure service. This standard moves beyond fragmented solutions and offers a unified strategy for securing your entire operation, from physical depots to the digital supply chain.

Don’t forget to check our previous blog on “Securing the grid: A deep dive into OT security for electrical substations” here.

Beyond the firewall: Securing physical and virtual assets

A common misconception is that cybersecurity is only about firewalls, diodes and software. TS 50701, which is based on the robust IEC 62443 standard, introduces a more holistic view through the concept of "Zones and Conduits." Those who are familiar with IEC 62443 will make a connection here.

Think of your entire railway as a city. You cannot and wouldn't protect your city with just one long wall around the perimeter. You'd have secure areas (zones) like a bank vault, a police station, or a hospital, and controlled pathways (conduits) to move between them. In fact as the terrorist attacks on September 11 have shown, terrorists are constantly looking at ways to launch attacks from within. The situation is not different as far as hackers and threat actors are concerned.

Zones: These are groupings of assets (both physical and logical) that share a common security requirement. A zone can be:
- Physical: A signaling control center, a maintenance depot, or a specific server room.
- Logical: Your passenger Wi-Fi network, the train control and management system (TCMS), or the station's passenger information system.
Conduits: These are the communication channels that connect zones. This could be the trackside-to-train radio link or the network cable connecting the control center to the track.

TS 50701 demands that you perform a risk assessment on each zone, not just the network as a whole. This assessment must account for all threats, including unauthorized physical access. The risk assessment must cover every aspect of operations including devices, systems, processes, networks, people and supply chains. You can build a risk/security score for your railway operations using a TS 50701-based assessment.

In practice: This means the physical security of a laptop in a signalling bungalow is just as much a part of your TS 50701 strategy as the firewall protecting it. The standard ensures you can't have strong cybersecurity without strong physical security.

Securing the entire ecosystem

TS 50701 was explicitly designed to cover the entire rail ecosystem. Here’s how it applies to your core railway infrastructure:

Railway stations and depots (fixed installations)

Your stations and depots are complex zones with multiple sub-systems. Using the "zones and conduits" model, you would partition them:

High-security zone: The station's or depot's local signalling and control room. Access is highly restricted, and all data flow (conduit) is monitored and filtered.
Operational zone: Systems like CCTV, public address systems, and staff communications.
Public zone: The passenger-facing Wi-Fi and digital information screens. This zone must be completely isolated from the operational and signalling zones to prevent an attack from "jumping" across.

Rolling stock

A train is a mobile, interconnected network—a "zone" on wheels. TS 50701 provides a framework for securing it:

TCMS & Critical Controls: The train's "brain" (e.g., brakes, doors, propulsion) is its own high-security zone.
Onboard Systems: Passenger Wi-Fi, infotainment, and diagnostic data recorders are in separate, lower-trust zones.
Conduits: The standard mandates securing the communication links, especially the train-to-ground radio, which is a primary attack vector.

Securing the chain: Your biggest risk may be your supplier

A train is a system of systems that include many moving parts built by dozens of different suppliers operating at varied security levels. How do you ensure a component you bought is secure?

This is one of the most critical areas TS 50701 addresses. The standard is not just for railway operators; it was written to provide a common security language for the entire supply chain, including integrators and manufacturers.

Here’s how it secures your supply chain:

Sets the benchmark: You no longer need to invent your own cybersecurity requirements for suppliers. You can mandate that components (like a new signalling system or an onboard router) be "TS 50701-compliant."
Enforces third-party risk management (TPRM): The standard’s lifecycle approach requires you to manage security from the procurement and design phases, not just after installation. This means:
- Supplier vetting: Asking suppliers how they develop secure software and hardware.
- Security deliverables: Demanding evidence from your vendors, such as risk assessments, security test results, and plans for managing vulnerabilities. Are they compliant with IEC 62443-4-2?
- Lifecycle management: Ensuring the supplier has a plan to provide security patches and support for the component's entire 20-30 year lifespan.

By embedding TS 50701 into your procurement contracts, you are effectively extending your security posture to your entire supply chain, protecting your railway from inheriting vulnerabilities.

TS 50701 is the security rulebook

TS 50701 is more than a technical document; it's a comprehensive security-management framework. It provides railway companies with a clear, auditable, and internationally-recognized "rulebook" to:

Integrate physical and cybersecurity under one strategy.
Secure every asset, from the central control room to the last car on the train.
Manage the significant risks posed by a complex global supply chain.

Adopting this standard is the most significant step a railway operator can take to protect its assets, ensure passenger safety, and build a truly resilient railway for the future.

Talk to our TS 50701 expert and discuss your railway security challenges here.