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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Starting with "O" (211)

Disclaimer
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
Offshore work	Human and Organisational Factor	Directive	Directive 2003/88/EC of the European Parliament and of the Council of 4 November 2003 concerning certain aspects of the organisation of working time
OFOD	EU Policy	Glossary	Glossary for transport statistics - 5TH EDITION 2019
OHIM	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
OIML	International Standard	EU Technical Document	CEN CENELEC ABBRAVIATION ACRONYM 2025	Latest release
OIS	ERTMS	Glossary	ERTMS/ATO Glossary - version 2 on 05.07.2023
OIW	International Standard	EU Technical Document	CEN CENELEC ABBRAVIATION ACRONYM 2025	Latest release
OJ	Control-Command and Signalling	Application Guide	GUI/CCS TSI/2023 Version 1.0 17/06/2024 Guide for the application of the CCS TSI 2023/1695 In accordance with Article 19(3) of Regulation (EU) 2016/796 of the European Parliament and of the Council of 11 May 2016
OJ	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
OJ	Vehicles / VA	Application Guide	GUI/LOC&PAS TSI/2021 - version 3.0 on 15/02/2021 Guide for the application of the LOC&PAS TSI (Commission Regulation (EU) No 1302/2014 of 18 November 2014 and amended by the Commission Implementing Regulation (EU) 2019/776) In accordance with Article 19(3) of Regulation (EU) 2016/796 of the European Parliament and of the Council of 11 May 2016
OJ/OJEU	Interoperability	Application Guide	Application_guide GUI/TSI/2023 Version 1.0 20/12/2023Guide for the application of the Technical Specifications for Interoperability (TSIs)
OJEU	International Standard	EU Technical Document	CEN CENELEC ABBRAVIATION ACRONYM 2025	Latest release
OL	ERTMS	Technical Document	ERTMS/ETCS - Glossary of Terms and Abbreviations - version : 4.0.0 - date 05/07/2023
OLN	Freight	Glossary	Transport of dangerous goods. Risks Management Framework. Framework glossary v. 1.0/2018
OM	International Standard	ISO	ISO 3166 (en) - Online Browsing Platform (OBP) Codes for the representation of names of countries and their subdivisions — Part 1: Country code
On sight mode	ERTMS	Technical Document	ERTMS/ETCS - Glossary of Terms and Abbreviations - version : 4.0.0 - date 05/07/2023
On track Machines (OTMs)	Vehicles / VA	TSI	Commission Regulation (EU) No 1302/2014 of 18 November 2014 concerning a technical specification for interoperability relating to the rolling stock — locomotives and passenger rolling stock subsystem of the rail system in the European Union
On-board control command and signalling	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)
On-board control-command and signalling	Interoperability	Directive	Directive (EU) 2016/797 of the European Parliament and of the Council of 11 May 2016 on the interoperability of the rail system within the European Union (recast)
On-board Energy Measurement System (EMS)	Vehicles / VA	TSI	Commission Regulation (EU) No 1302/2014 of 18 November 2014 concerning a technical specification for interoperability relating to the rolling stock — locomotives and passenger rolling stock subsystem of the rail system in the European Union
On-Board equipment	ERTMS	Technical Document	ERTMS/ETCS - Glossary of Terms and Abbreviations - version : 4.0.0 - date 05/07/2023

Common Safety Method
Conformity Assessment
Control-Command and Signalling
Data Protection
Energy
Entity in Charge of Maintenance
ERTMS
EU Policy
Freight
Human and Organisational Factor
Infrastructure
International Relations
International Standard
Interoperability
Noise
Operation
Persons with Reduced Mobility
Railway Tunnels
Registers
Regulation
RNE Glossary
Safety / SSC-SA
Security
SERA_EU Transport
Single Market Mutual Recognition Conformity Assessment
Telematics Applications for Freight
Telematics Applications for Passenger
Vehicles / VA
Withdrawn

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