SIST-TP CLC/TR 50542-3:2026

• Abstract:

  The scope of this document is the definition of the functional interface between the TDC and other train systems. These "Other Train Systems" are the train systems interfacing with the TDC excluding the displays (CLC/TR 50542-2), ETCS/STM onboard (Subset-121) and already designed class B ATP systems.; The functional interface deals with data exchanged between the TDC and these train systems as shown in Figure 1.; The TDC is defined in document CLC/TR 50542-1.; (...)

• Status: Published
• Publication Date: 01-Sep-2026
• ICS: 35.240.60 - IT applications in transport
• ICS: 45.020 - Railway engineering in general
• Technical Committee: ŽEN - Electrical applications for railways
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 11-Jun-2026
• Due Date: 16-Aug-2026
• Completion Date: 02-Sep-2026
• Ref Project: CLC/TR 50542-3:2026 - Railway applications - Driver's cab Train Display Controller (TDC) - Part 3: Other Train Systems FIS

• Replaces: SIST-TP CLC/TR 50542-3:2017 - Railway applications - Driver's cab train Display Controller (TDC) - Part 3: Other train systems FIS
• Effective Date: 01-Oct-2026

Overview

SIST-TP CLC/TR 50542-3:2026 is a technical report developed by the Slovenian Institute for Standardization (SIST) in cooperation with the European Committee for Electrotechnical Standardization (CENELEC). The standard focuses on railway applications, specifically on the functional interface between the Driver's cab Train Display Controller (TDC) and Other Train Systems (OTS), excluding display systems and certain onboard signaling systems. This document supersedes the previous edition from 2017, providing an updated approach for efficient data exchange and system integration in train control environments.

This technical report plays a crucial role in enabling interoperability, supporting market openness, and reducing life-cycle costs by defining clear specifications for the interaction of train subsystems with the TDC. The defined interface framework facilitates easier upgrades, maintenance, and component replacement in both new rolling stock and refurbishment projects.

Key Topics

• Functional Interface Definition: Detailed description of the interface for data exchange between TDC and Other Train Systems, excluding displays, ETCS/STM onboard, and existing class B ATP systems.
• Terminology & Abbreviations: Establishes common language, including essentials like OTS (Other Train Systems), TDC (Train Display Controller), and CCTV (Closed-Circuit Television).
• Function Categories:
  • State: Input from OTS (e.g., brake status, alarm signals) sent to TDC.
  • Command: Output from TDC to OTS (e.g., door control requests).
  • Provide Video: OTS (such as CCTV systems) sending video streams to TDC.
  • Management Functions: Exchange of status and management information between TDC and various OTS.
• Application Examples: Illustrative use cases include parking brake status, passenger alarm activation, door operations, CCTV video feeds, and onboard safety alerts (e.g., hot box detection).
• Upgrade & Maintenance: Clear functional definitions simplify the process of changing TDCs or OTS for maintenance or obsolescence management.

Applications

SIST-TP CLC/TR 50542-3:2026 is highly relevant for:

• Rolling Stock Manufacturers: Ensuring new trains and refurbishments can integrate TDCs with a variety of train systems efficiently.
• Rail Operators and Maintainers: Facilitating streamlined maintenance, system upgrades, and improved turnaround through standardized interfaces.
• System Integrators: Supporting easier tendering and procurement by providing functional reference points for subsystems integration.
• Safety and Surveillance Solutions: Enabling direct interfacing of critical systems, like CCTV and safety alarms, to the driver's cab display environment.
• Lifecycle Cost Management: Lowering operational costs by reducing the complexity and risk associated with component swaps and system updates.

Related Standards

To provide comprehensive interoperability and full technical coverage, the following documents and standards are closely related to SIST-TP CLC/TR 50542-3:2026:

• CLC/TR 50542-1: Railway applications - Driver's cab Train Display Controller (TDC) - Part 1: General Architecture
• CLC/TR 50542-2: Railway applications - Driver's cab Train Display Controller (TDC) - Part 2: Display systems Functional Interface Specification (FIS)
• Subset 121: DMI-EVC Interface (For details on ETCS/STM onboard system interfaces)
• Relevant ICS Codes: 35.240.60 (IT Applications in Transport), 45.020 (Railway Engineering in General)

By adhering to this technical report, stakeholders in the railway industry can achieve more reliable, maintainable, and interoperable control systems, enhancing both safety and operational efficiency in modern rail operations.

SLOVENSKI STANDARD
01-oktober-2026
Nadomešča:
SIST-TP CLC/TR 50542-3:2017
Železniške naprave - Krmilnik vlakovnega prikazovalnika (TDC) v strojevodskem
prostoru - 3. del: Drugi vlakovni sistemi (FIS)
Railway applications - Driver's cab Train Display Controller (TDC) - Part 3: Other Train
Systems FIS
Bahnanwendungen - Display-Steuereinheit (TDC) für Führerräume - Teil 3: Andere
Zugsysteme FIS
Applications ferroviaires - Contrôleur d'écrans de cabine (TDC) - FIS pour autres
systèmes de train
Ta slovenski standard je istoveten z: CLC/TR 50542-3:2026
ICS:
35.240.60 Uporabniške rešitve IT v IT applications in transport
prometu
45.020 Železniška tehnika na Railway engineering in
splošno general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

TECHNICAL REPORT CLC/TR 50542-3

RAPPORT TECHNIQUE
TECHNISCHER REPORT June 2026
ICS 35.240.60; 45.020 Supersedes CLC/TR 50542-3:2016
English Version
Railway applications - Driver's cab Train Display Controller
(TDC) - Part 3: Other Train Systems FIS
Applications ferroviaires - Contrôleur d'écrans de cabine Bahnanwendungen - Display-Steuereinheit für Führerräume
(TDC) - FIS pour autres systèmes de train (TDC) - Teil 3: Andere Zugsysteme FIS

This Technical Report was approved by CENELEC on 2026-05-18.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,
Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the
Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Türkiye and the United Kingdom.

European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2026 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. CLC/TR 50542-3:2026 E

Contents Page
European foreword .3
Introduction .4
1 Scope .5
2 Normative references .5
3 Terms and definitions .5
4 Symbols and abbreviations .6
5 General principles.6
6 Functions .7
6.1 General .7
6.2 State .7
6.3 Command .7
6.4 Provide Video .8
6.5 Management functions .8
6.5.1 TDS Status .8
6.5.2 OTS Status .8
6.6 Relationship between CLC/TR 50542-2:2025 and this document .8
Annex A (informative) Examples of OTS functions . 10
Bibliography . 11
European foreword
This document (CLC/TR 50542-3:2026) has been prepared by CLC/TC 9X “Electrical and electronic
applications for railways”.
This document supersedes CLC/TR 50542-3:2016.
3:2016:
— Clause 2: the normative references have been deleted.
— Note 1 added to term entry 3.2.
— Note 1 added to term entry 3.3.
— Clause 4: TDS added.
— Clause 5: addition of a reference to Annex A.
— 5.1: direction is clearly described from the OTS and TDC point of view.
— 5.2: clarification added about the use of the function.
— 5.3: a note has been added to clarify the source of the request.
— Annex A:
— application to CCTV has been clarified,
— OTS Onboard hot box detecting system added, as an example of safety related OTS.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CENELEC shall not be held responsible for identifying any or all such patent rights.
Any feedback and questions on this document should be directed to the users’ national committee. A complete
listing of these bodies can be found on the CENELEC website.
Introduction
The extent of CLC/TR 50542-3 is the functional interface between the Other Train Systems (OTS) and the TDC.
The functional definition of this interface is a key feature in the process to increase market development, for
instance:
— by introducing more suppliers for new rolling stock development and for driver's cab refurbishment;
— by easing the control of maintenance and the replacement processes;
— by decreasing the related equipment Life cycle cost.
In this document, the train borne systems and the TDC are considered only regarding their functionalities and
not as physical devices.
The CLC/TR 50542 series consists of three documents:
— CLC/TR 50542-1, Railway applications — Driver's cab Train Display Controller (TDC) — Part 1: General
architecture;
— CLC/TR 50542-2, Railway applications — Driver's cab Train Display Controller (TDC) — Part 2: Display
systems FIS;
— CLC/TR 50542-3, Railway applications — Driver's cab Train Display Controller (TDC) — Part 3: Other train
systems FIS (this document).
This series of documents is not a standard but the result of a study on the future view of the system. They do
not describe an existing solution for the TDS.
These documents are not written to be used in call for tenders because they are not sufficient. However, they
can serve as a basis for future development and standardization including new technologies. These documents
are a first step and may be completed later.
NOTE In case of existing discrepancies between CLC/TR 50542-1:2025 and CLC/TR 50542-3:2026, the present
document prevails.
1 Scope
The scope of this document is the definition of the functional interface between the TDC and other train systems.
These “Other Train Systems” are the train systems interfacing with the TDC excluding the displays
(CLC/TR 50542-2), ETCS/STM onboard (Subset-121) and already designed class B ATP systems.
The functional interface deals with data exchanged between the TDC and these train systems as shown in
Figure 1.
The TDC is defined in document CLC/TR 50542-1.
...