What is the difference between a Notified Body (NoBo) and a Designated Body (DeBo)?

The main difference lies in the rules they assess. A Notified Body (NoBo) checks compliance with European Technical Specifications for Interoperability (TSI), whereas a Designated Body (DeBo) checks compliance with specific National Notified Technical Rules (NNTR) of the country where the system will operate.

Is a NoBo certificate required for all railway projects?

A NoBo certificate is mandatory for any new, renewed, or upgraded railway subsystem that falls under the Interoperability Directive within the European Union. It ensures the system is compatible with the trans-European rail network.

What are TSIs in the context of Notified Bodies?

TSIs (Technical Specifications for Interoperability) are the harmonized European standards that define the technical and operational requirements for each subsystem (e.g., Energy, Infrastructure, Control-Command). The NoBo uses these standards as the checklist for assessment.

The Gatekeepers of Interoperability: What is a Notified Body (NoBo)?

Ensure EU railway compliance with a Notified Body. Learn how NoBos validate Technical Specifications for Interoperability (TSI) and issue essential CE certificates.

December 11, 2025 8:22 am

What is a Notified Body (NoBo)?

A Notified Body (NoBo) is an independent organization designated by an EU Member State to assess the conformity of railway subsystems and interoperability constituents against Technical Specifications for Interoperability (TSI).

The primary role of a NoBo is to conduct the “EC verification” procedure. When a manufacturer or contracting entity wants to place a railway product (such as a signaling system or rolling stock) on the European market, the NoBo validates that the product meets all relevant EU-wide requirements, leading to the issuance of an EC Certificate of Conformity.

Key Responsibilities of a NoBo

Conformity Assessment: Verifying that design, production, and final testing comply with TSIs.
Certification: Issuing the EC certificate required for the CE marking of components.
Surveillance: Periodically auditing manufacturers’ quality management systems (QMS) to ensure continued compliance.
Technical Documentation: Reviewing the technical files (TF) that prove the interoperability of the subsystem.

The Assessment Landscape: NoBo vs. DeBo vs. AsBo

In the railway sector, third-party assessment is split into three distinct roles depending on the regulations being checked. Understanding the difference is crucial for project approval.

Role	Full Name	Scope of Assessment	Reference Standard
NoBo	Notified Body	European Interoperability	TSI (Technical Specifications for Interoperability)
DeBo	Designated Body	National Compatibility	NNTR (National Notified Technical Rules)
AsBo	Assessment Body	Safety Management & Risk	CSM-RA (Common Safety Methods for Risk Assessment)

The EC Verification Process

The path to obtaining a NoBo certificate typically follows a structured workflow involving modules (e.g., Module SB for Type Examination, Module SD for Quality Management):

1. Application and Design Review

The applicant submits technical files. The NoBo reviews the design against the relevant TSI (e.g., TSI CCS for signaling, TSI LOC&PAS for trains).

2. Audit and Inspection

The NoBo performs on-site audits of the manufacturing facility or witnesses tests to ensure the physical product matches the approved design.

3. Certification

Upon successful verification, the NoBo issues the Certificate of Verification. This document is a mandatory prerequisite for the National Safety Authority (NSA) or ERA to authorize the placing of the subsystem into service.