Ensuring Safe Rails: EN 15595 for Onboard Signaling Systems Explained

EN 15595 defines the functional and safety requirements for railway onboard control-command and signaling systems, ensuring safe and interoperable train operation.

November 23, 2023 7:46 pm

What Is EN 15595?

EN 15595 is a European standard that defines the functional and safety requirements for onboard control-command and signaling systems in trains.
It ensures that trainborne systems operate reliably, safely, and interoperably across European rail networks.

Importance of EN 15595 in Railway Safety

Modern railway operations rely on complex onboard signaling systems to maintain safe train separation and efficient traffic flow.
EN 15595 ensures these systems meet rigorous functional and safety requirements, reducing the risk of accidents and operational failures.

Specifies functional safety requirements for onboard systems
Supports interoperability across different national rail networks
Aligns with SIL (Safety Integrity Level) assessments
Facilitates compliance with ETCS and ERTMS regulations

Scope of the Standard

EN 15595 focuses on the trainborne aspects of control-command and signaling, covering software, hardware, and integration with trackside systems.

Onboard signaling equipment and interfaces
Control-command software and safety logic
Integration with ETCS / ERTMS levels
Functional verification and validation procedures
Failure detection, alarm, and fallback mechanisms

Key Technical Requirements

The standard establishes minimum safety and functional performance criteria for onboard systems.

Main Technical Parameters

Parameter	Purpose	Operational Impact
Functional Safety (SIL)	Specifies the required Safety Integrity Level	Ensures predictable safety performance under all conditions
Software Reliability	Ensures correct system logic execution	Prevents signaling errors and potential collisions
Interface Compatibility	Defines communication with trackside systems	Maintains interoperability across European networks
Failure Handling	Specifies fallback and alarm procedures	Minimizes operational risk in case of faults

Relationship with Other Standards

EN 15595 complements ETCS and ERTMS standards, providing detailed onboard requirements that support compliance with higher-level specifications.
It also aligns with EN 50126/50128/50129 for railway software and hardware safety.

Supports ETCS Level 1–3 onboard systems
Integrates with European Train Control Systems
Aligns with functional safety standards EN 50126–50129

Who Uses EN 15595?

Railway operators, rolling stock manufacturers, signaling equipment suppliers, and certification bodies use EN 15595 to ensure that onboard systems meet European safety and interoperability requirements.