European Union Agency for Railways

ERA Railway Terminology visual v0 featured

ERA Railway Terminology Collection

Last updated: 5 December 2025.

The ERA Railway Terminology Collection gathers terms and abbreviations that are contained in the EU legal framework for railway, technical documents produced by bodies which are engaged in the development of important evolution in the railway system and other relevant glossaries.

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The file you will get by clicking the "Download the full Terminology" button below is in CSV format. To convert it to a readable Excel file:

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Starting with "O" (211)

ERA Railway Terminology Collection is a consultation tool, developed to support the sharing of information through the actors involved in running the Single European Railway Area (SERA). The responsibility for the correctness, completeness, accuracy, or reliability of the information in ERA RTC lays upon the authors of the definitions, as they derive from reference documents having their own preparation and approval flow. Users cannot call ERA liable for the use they make of the content. Please consider that when the collection is exported (.csv) and then printed or converted, it becomes uncontrolled.
Term Context Document Type Origin document

Operational personal data

Data Protection

Regulation

Regulation (EU) 2018/1725 of the European Parliament and of the Council of 23 October 2018 on the protection of natural persons with regard to the processing of personal data by the Union institutions, bodies, offices and agencies and on the free movement of such data, and repealing Regulation (EC) No 45/2001 and Decision No 1247/2002/EC

Operational Point (OP)

Infrastructure

Regulation

Commission Implementing Regulation (EU) 2019/777 of 16 May 2019 on the common specifications for the register of railway infrastructure and repealing Implementing Decision 2014/880/EU

Operational point at end of section of line

Infrastructure

Regulation

Commission Implementing Regulation (EU) 2019/777 of 16 May 2019 on the common specifications for the register of railway infrastructure and repealing Implementing Decision 2014/880/EU

Operational point at start of section of line

Infrastructure

Regulation

Commission Implementing Regulation (EU) 2019/777 of 16 May 2019 on the common specifications for the register of railway infrastructure and repealing Implementing Decision 2014/880/EU

Operational regime

Infrastructure

Regulation

Commission Implementing Regulation (EU) 2019/777 of 16 May 2019 on the common specifications for the register of railway infrastructure and repealing Implementing Decision 2014/880/EU

Operational test scenario

Control-Command and Signalling

Regulation

Commission Implementing Regulation (EU) 2023/1695 of 10 August 2023 on the technical specification for interoperability relating to the control-command and signalling subsystems of the rail system in the European Union and repealing Regulation (EU) 2016/919

Operator

Telematics Applications for Passenger

Application Guide

TAP TSI Annex B.50 Timetable application_guide - version 1.0 of 06/12/2013

Operator interface

Single Market Mutual Recognition Conformity Assessment

Regulation

Regulation (EU) 2019/1020 of the European Parliament and of the Council of 20 June 2019 on market surveillance and compliance of products and amending Directive 2004/42/EC and Regulations (EC) No 765/2008 and (EU) No 305/2011

Latest release

Operator of a recharging point

Energy

Regulation

Regulation (EU) 2023/1804 of the European Parliament and of the Council of 13 September 2023 on the deployment of alternative fuels infrastructure, and repealing Directive 2014/94/EU

Operator of a refuelling point

Energy

Regulation

Regulation (EU) 2023/1804 of the European Parliament and of the Council of 13 September 2023 on the deployment of alternative fuels infrastructure, and repealing Directive 2014/94/EU

Operator of service facility

SERA_EU Transport

Directive

Directive 2012/34/EU of the Parliament and of the Council of 21 November 2012 establishing a single European railway area (recast)

Operator of service facility

RNE Glossary

Glossary

RNE Glossary - NS_CID_Glossary_2025

Latest release

OPET

EU Policy

EU Technical Document

Technical document from the Publications Office of the European Union - ‘Style guide’ Coordination Interinstitutional Style Guide - version on 19.04.2022

Opportunity costs

EU Policy

Glossary

The Social Costs of Transport - February 1997

Optical characteristics

Interoperability

Decision

Commission Decision of 30 November 2009 on the reference document referred to in Article 27(4) of Directive 2008/57/EC of the European Parliament and of the Council on the interoperability of the rail system within the Community. (2009/965/EC)

Option

Freight

Glossary

Transport of dangerous goods. Risks Management Framework. Framework glossary v. 1.0/2018

Optional GSM-R functions

Infrastructure

Regulation

Commission Implementing Regulation (EU) 2019/777 of 16 May 2019 on the common specifications for the register of railway infrastructure and repealing Implementing Decision 2014/880/EU

ORBG

ERTMS

Technical Document

ERTMS/ETCS - Glossary of Terms and Abbreviations - version : 4.0.0 - date 05/07/2023

ORD

ERTMS

Glossary

ERTMS/ATO Glossary - version 2 on 05.07.2023

ORD

Freight

Glossary

Transport of dangerous goods. Risks Management Framework. Framework glossary v. 1.0/2018