prEN IEC 61375-2-3:2025

SLOVENSKI STANDARD
01-februar-2026
Železniške elektronske naprave - Komunikacijsko omrežje vlaka (TCN) - 2-3. del:
Komunikacijski profil TCN
Electronic railway equipment - Train communication network (TCN) - Part 2-3: TCN
communication profile
Elektronische Betriebsmittel für Bahnen - Zug-Kommunikations-Netzwerk (TCN) - Teil 2-
3: TCN-Kommunikationsprofil
Matériel électronique ferroviaire - Réseau embarqué de train (TCN) - Partie 2-3: Profil de
communication TCN
Ta slovenski standard je istoveten z: prEN IEC 61375-2-3:2025
ICS:
35.240.60 Uporabniške rešitve IT v IT applications in transport
prometu
45.060.01 Železniška vozila na splošno Railway rolling stock in
general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

9/3292/CDV
COMMITTEE DRAFT FOR VOTE (CDV)
PROJECT NUMBER:
IEC 61375-2-3 ED2
DATE OF CIRCULATION: CLOSING DATE FOR VOTING:
2025-12-26 2026-03-20
SUPERSEDES DOCUMENTS:
9/3102/CD, 9/3140A/CC
IEC TC 9 : ELECTRICAL EQUIPMENT AND SYSTEMS FOR RAILWAYS
SECRETARIAT: SECRETARY:
France Mr Denis MIGLIANICO
OF INTEREST TO THE FOLLOWING COMMITTEES: HORIZONTAL FUNCTION(S):

ASPECTS CONCERNED:
SUBMITTED FOR CENELEC PARALLEL VOTING NOT SUBMITTED FOR CENELEC PARALLEL VOTING
Attention IEC-CENELEC parallel voting
The attention of IEC National Committees, members of
CENELEC, is drawn to the fact that this Committee Draft
for Vote (CDV) is submitted for parallel voting.
The CENELEC members are invited to vote through the
CENELEC online voting system.
This document is still under study and subject to change. It should not be used for reference purposes.
Recipients of this document are invited to submit, with their comments, notification of any relevant patent rights of
which they are aware and to provide supporting documentation.
Recipients of this document are invited to submit, with their comments, notification of any relevant “In Some Countries”
clauses to be included should this proposal proceed. Recipients are reminded that the CDV stage is the final stage for
submitting ISC clauses. (SEE AC/22/2007 OR NEW GUIDANCE DOC).

TITLE:
Electronic railway equipment - Train communication network (TCN) - Part 2-3: TCN communication
profile
PROPOSED STABILITY DATE: 2028
NOTE FROM TC/SC OFFICERS:
electronic file, to make a copy and to print out the content for the sole purpose of preparing National Committee positions.
You may not copy or "mirror" the file or printed version of the document, or any part of it, for any other purpose without
permission in writing from IEC.

IEC CDV 61375-2-3 © IEC 2025
Link to Committee Draft for Vote (CDV) online document:
Click here
How to access
This link leads you to the Online Standards Development (OSD) platform for National Mirror
Committee’s (NMC) comments. The project draft may be found further down this document.

Resource materials
We recommend NCs to review the available materials to better understand the member commenting
on the OSD platform. This includes the:
• OSD NC roles overview
• How to add and submit comments to the IEC

Contact
Should you require any assistance, please contact the IEC IT Helpdesk.

IEC CDV 61375-2-3 © IEC 2025
CONTENTS
CONTENTS . 3
FOREWORD . 16
INTRODUCTION . 18
1 Scope . 20
2 Normative references . 21
3 Terms, definitions, abbreviations, acronyms, and conventions . 21
3.1 Terms and definitions. 21
3.2 Abbreviations and acronyms . 26
3.3 Conventions . 28
3.3.1 Base of numeric values . 28
3.3.2 Character strings and citations . 29
3.3.3 Naming conventions . 29
3.3.4 Diagram conventions . 29
3.3.5 Annotation of data structures . 30
4 Architecture . 30
4.1 General . 30
4.2 Physical train architecture (system breakdown) . 31
4.2.1 General . 31
4.2.2 Train network architectures . 31
4.2.3 Closed Trains . 34
4.2.4 Directions . 36
4.2.5 Consist and vehicle basic properties . 37
4.3 Logical Train Architecture (Functional Breakdown) . 38
4.3.1 General . 38
4.3.2 Service classification . 38
4.3.3 Operational Services Overview . 39
4.3.4 Service Provider . 39
5 Common ETB framework . 40
5.1 General . 40
5.1.1 Overview . 40
5.1.2 Interoperability. 40
5.2 CSTINFO telegram . 40
5.2.1 General . 40
5.2.2 Closed train support (Option) . 40
5.2.3 Protocol . 41
5.2.4 CSTINFO classes . 41
5.2.5 CSTINFO Notification Message . 41
5.2.6 CSTINFO Request . 42
5.3 Train topology database. 44
5.3.1 General . 44
5.3.2 Computation of the TTDB . 45
5.3.3 Data structure . 50
5.3.4 Train Topology Database for multiple ETBs (Option) . 58
5.3.5 TTDB access . 58
5.4 Service Addressing . 58
5.4.1 General . 58
IEC CDV 61375-2-3 © IEC 2025
5.4.2 TCN Domain Name System (TCN-DNS). 59
5.4.3 TCN Domain Names . 60
5.4.4 TCN-URI Scheme . 60
5.4.5 Mapping TCN-URI to IP address . 66
5.4.6 Support of other URI schemas . 68
5.5 TCN-DNS Server . 68
5.5.1 General . 68
5.5.2 Architecture . 68
5.5.3 Functional address resolution . 68
5.5.4 Protocol . 71
5.5.5 Multiple Domains . 71
5.6 Data exchange . 71
5.6.1 General . 71
5.6.2 Operational network communication . 71
5.6.3 OMTS network communication . 72
5.6.4 Quality of Service (QoS) . 72
5.7 Announcement of supported functions . 72
5.8 Beacon Telegrams and Beacon Proxy Function (Option) . 72
5.8.1 General . 72
5.8.2 Beacon telegram exchange. 73
5.8.3 Beacon telegram . 74
5.8.4 Beacon Proxy function . 76
6 ETB Control Service . 77
6.1 General . 77
6.2 Communication model . 78
6.3 ECSP Supervision . 78
6.4 ECSP Interconnection . 79
6.4.1 General . 79
6.4.2 ETBCTRL telegram exchange selection . 79
6.4.3 ETBCTRL telegram transmission . 79
6.4.4 Structure of the ETBCTRL telegram . 80
6.4.5 Operational train directory computation process . 82
6.5 Function "Leading" . 85
6.5.1 General . 85
6.5.2 Function primitives . 85
6.5.3 ECSP to ECSP protocol . 86
6.6 Function "Confirmation/Correction" . 90
6.6.1 General . 90
6.6.2 Function primitives . 90
6.6.3 ECSP to ECSP protocol . 91
6.6.4 State diagram . 94
6.6.5 ECSC Failure . 96
6.7 Computation of the operational train directory . 96
6.7.1 General . 96
6.7.2 Action setCorrInfo . 96
6.7.3 Action computeOpTrnDir. 100
6.8 Function "Sleep Mode" (Option) . 103
6.8.1 General . 103
6.8.2 Sleep Mode Use Case (informal) . 103
IEC CDV 61375-2-3 © IEC 2025
6.8.3 Exclusivity . 105
6.8.4 Function primitives . 105
6.8.5 ECSP to ECSP protocol . 106
6.9 Function "Wake-up" (Option) . 109
6.9.1 General . 109
6.9.2 Function primitives . 110
6.9.3 ECSP to ECSP protocol . 110
6.9.4 DC Voltage . 113
6.9.5 Wake-up detection . 115
6.10 Function "Passive Consist Detection" (Option) . 115
6.10.1 General . 115
6.10.2 Function primitives . 115
6.10.3 ECSP to ECSP protocol . 116
6.10.4 PCD load . 119
6.10.5 PCD measurement cycle . 119
6.10.6 Computing and evaluating the train gap list . 120
6.11 Function "DC based Consist Orientation Detection" (Option) . 121
6.11.1 General . 121
6.11.2 Function primitives . 121
6.11.3 DC Voltage for consist orientation detection . 122
6.11.4 Consist orientation detection procedure . 122
Annex A (normative) Train Real-Time Data Protocol (TRDP) . 123
A.1 General . 123
A.2 Lower Layers . 123
A.2.1 Data link layer . 123
A.2.2 Network Layer . 123
A.2.3 Transport Layer . 124
A.3 TRDPFCS computation . 125
A.4 Interaction between TRDP user and TRDP Layer . 126
A.5 Communication Identifier (ComId) . 127
A.6 Process Data . 129
A.6.1 Communication model . 129
A.6.2 Roles . 129
A.6.3 Communication pattern . 130
A.6.4 Addressing . 134
A.6.5 PD-PDU . 134
A.6.6 Interaction between application and TRDP protocol layer . 137
A.6.7 Topology counter check . 145
A.6.8 State Machine . 146
A.7 Message Data . 150
A.7.1 Communication model . 150
A.7.2 Roles . 151
A.7.3 Communication pattern . 151
A.7.4 Addressing . 152
A.7.5 MD-PDU . 152
A.7.6 Interaction between application and TRDP layer . 155
A.7.7 Topology counter check . 160
A.7.8 MD protocol state machine . 161
A.7.9 TCP Connection Handling . 169
IEC CDV 61375-2-3 © IEC 2025
A.8 Message data echo server (option) . 170
Annex B (normative) Safe Data Transmission (SDTv2 / SDTv4) . 171
B.1 Overview of SDTvX (informal) . 171
B.2 General . 171
B.3 Safety functional requirements . 172
B.4 Safety measures . 172
B.5 Operational states of the SDTvX channel . 173
B.6 Data presentation . 174
B.7 SC-32 for SID and SafetyCode for SDTv2 as well as variant 1 of SDTv4 and
for SafetyCode (CRC1) of SDTv4 variant 2 . 174
B.8 SC-32 for SafetyCode CRC2 of variant 2 of SDTv4 . 175
B.9 SID for SDTv2 and SDTv4 . 176
B.9.1 SID for SDTv2 . 176
B.9.2 SID for SDTv4 . 177
B.9.3 SID configuration . 178
B.9.4 Reserved SMI values . 178
B.10 Vital Data Packet . 179
B.10.1 SDTv2 VDPs: . 179
B.10.2 SDTv4 VDPs . 180
B.10.3 SDTv4CRC Computation: . 182
B.11 Exclusivity . 184
B.12 Configuration time parameters . 185
B.13 Safe data source (SDSRC) . 185
B.13.1 General . 185
B.13.2 Safe Data Preparation (Application) . 185
B.13.3 Safe data sending . 186
B.14 Safe data sink (SDSINK) . 187
B.14.1 General . 187
B.14.2 Definitions . 187
B.14.3 SDSINK States . 189
B.14.4 VDP Sampling . 190
B.14.5 VDP Integrity Check . 191
B.14.6 Sink time supervision . 192
B.14.7 Guard time check . 192
B.14.8 Latency monitoring . 193
B.14.9 Channel monitoring (SDTv2) . 196
B.14.10 SDTvX Application Interface . 197
B.14.11 Change of operational train composition . 197
B.15 Diagnosis and statistics . 197
B.16 Safe data transmission over MVB (informative) . 198
B.16.1 General . 198
B.16.2 MVB-VDP . 198
B.16.3 SDTV2 protocol deviations for MVB . 199
B.17 SDTvX with TRDP message data . 199
Annex C (informative) Train Real-Time Data Protocol Configuration (TRDP) . 201
C.1 General . 201
C.2 Device . 202
C.3 Device Configuration . 203
C.3.1 General . 203
IEC CDV 61375-2-3 © IEC 2025
C.3.2 Memory Block List . 203
C.4 Bus Interface List . 204
C.4.1 General . 204
C.4.2 Bus Interface . 204
C.5 Mapped Device List . 214
C.5.1 General . 214
C.5.2 Mapped Bus Interface Parameters . 215
C.6 Intentionally left blank . 217
C.7 Debug Parameters . 217
C.8 Data Set List . 218
C.8.1 General . 218
C.8.2 DataSet Element . 220
C.8.3 Examples of DataSets . 221
Annex D (informative) Access to End Device (ED) statistics . 226
D.1 General . 226
D.2 Structures . 226
D.2.1 General . 226
D.2.2 Global Statistics . 226
D.2.3 Subscriber Statistics . 227
D.2.4 Publisher Statistics . 228
D.2.5 UDP Listener Statistics . 228
D.2.6 TCP Listener Statistics . 228
D.2.7 Redundancy Statistics . 229
D.2.8 Join Statistics . 229
D.3 ED interface for statistics data access . 229
D.3.1 General . 229
D.3.2 TRDPPD interface . 229
D.3.3 TRDP statistics API . 230
Annex E (informative) Service interface . 232
E.1 General . 232
E.2 Service provider . 233
E.2.1 Proxies . 233
E.2.2 Performance . 233
E.3 ECSP interface . 233
E.3.1 General . 233
E.3.2 ECSP control telegram . 233
E.3.3 ECSP status telegram . 234
E.3.4 ECSP confirmation/correction . 236
E.3.5 ECSP train wake-up . 238
E.3.6 ECSP passive consist detection . 239
E.3.7 ECSPDC based Consist Orientation Detection . 242
E.4 TTDB manager interface . 244
E.4.1 General . 244
E.4.2 TTDB status information . 244
E.4.3 TTDB notification . 245
E.4.4 TTDB information - train directory . 246
E.4.5 TTDB information - static consist information . 246
E.4.6 TTDB information - train network directory information . 247
E.4.7 Operational train directory information . 248
IEC CDV 61375-2-3 © IEC 2025
E.4.8 Read TTDB. 248
E.5 DNS server interface . 249
E.5.1 DNS standard interface . 249
E.5.2 DNSTCN interface . 249
E.6 ETBN control interface . 253
E.6.1 General . 253
E.6.2 ETBN control and status data . 253
E.6.3 ETBN train network directory . 256
E.6.4 ETBN Beacon proxy . 256
E.6.5 ETBN HELLO extension write . 258
E.6.6 ETBN HELLO extension read. 259
Annex F (informative) SNMP Management Information Base (MIB) . 261
F.1 General . 261
F.2 TTDB-MIB . 261
F.3 TRDP-MIB . 265
Annex G (informative) Netconf YANG Model . 276
G.1 General . 276
G.2 IEC 61376-2-3-TTDB YANG model . 276
G.3 IEC 61376-2-3-TRDP YANG Model . 278
Annex H (informative) Train Inauguration Validation . 285
H.1 General . 285
H.2 Architecture . 286
H.3 Train inauguration validation (TI Validator) . 288
H.3.1 General . 288
H.3.2 Determine safety related inauguration parameters . 289
H.3.3 Train inauguration validation process . 290
H.3.4 TTDB pre-validation . 292
H.3.5 Validation train view checking . 293
H.3.6 Review of general failure modes . 294
H.3.7 Frequency of train inauguration validation . 295
H.4 Independent sensors for consist orientation and train end . 295
H.5 ETB operational states . 296
Annex I (informative) Freight Train Application . 297
I.1 General . 297
I.2 Differences between passenger trains and freight trains . 297
I.3 Freight train composition . 298
I.4 Selection of train backbone technology class . 298
I.5 Ethernet based train backbone for freight train operation . 299
I.6 Communication profile for freight train operation . 299
I.7 Functional safety considerations . 299
I.8 Freight train functions . 300
I.8.1 General . 300
I.8.2 Wake-up . 300
I.8.3 Passive consist detection (PCD) . 301
I.8.4 Train integrity . 301
I.8.5 Consist orientation . 302
I.8.6 Automatic decoupling (ADC) . 302
Bibliography . 305
IEC CDV 61375-2-3 © IEC 2025
Figure 1 – IEC 61375-2-3 as connecting element between train backbone and
application . 20
Figure 2 – Train structure in accordance to IEC 61375-1 (example) . 31
Figure 3 – Train structure seen from viewpoint of the communication profile (example) . 31
Figure 4 – Train network (example). 32
Figure 5 – Possible couplings of operational network and multimedia network . 33
Figure 6 – Gateway between operational network and multimedia network (example) . 34
Figure 7 – EXAMPLE three coupled Consists . 35
Figure 8 – EXAMPLE Closed Train . 35
Figure 9 – Service classification . 38
Figure 10 – CSTINFO notification data. 42
Figure 11 – CSTINFOCTRL telegram . 44
Figure 12 – TTDB management block diagram . 44
Figure 13 – TTDB Content . 45
Figure 14 – TTDB computation block diagram . 46
Figure 15 – Train directory computation state diagram . 47
Figure 16 – TTDB class diagram (example) . 50
Figure 17 – TCN-DNS name space with division into zones . 60
Figure 18 – TCN-URI Schema. 61
Figure 19 – Directions, orientations and numbers in train . 62
Figure 20 – TCN-URI resolving in a train . 69
Figure 21 – DNS protocol (case a without, case b with TTDB interrogation) . 71
Figure 22 – Beacon telegram exchange . 73
Figure 23 – Beacon distribution . 74
Figure 24 – BEACON-VDP . 75
Figure 25 – ETB control service model . 78
Figure 26 – ETBCTRL telegram exchange . 79
Figure 27 – ETBCTRL telegram . 80
Figure 28 – Operational train directory computation block diagram . 83
Figure 29 – ETBCTRL processing state diagram . 84
Figure 30 – Leading sequence diagram . 86
Figure 31 – Leading vehicle function state machine block diagram . 87
Figure 32 – State diagram of leading function . 88
Figure 33 – Confirmation sequence diagram . 91
Figure 34 – Confirmation/correction function state machine block diagram. 92
Figure 35 – Correction/confirmation protocol sequence chart (example) . 93
Figure 36 – Unconfirm protocol sequence chart (example) . 94
Figure 37 – Confirmation/correction state diagram . 95
Figure 38 – Action "setCorrInfo" block diagram . 97
Figure 39 – Train composition consistency check examples . 100
Figure 40 – Computation of the operational train directory . 101
Figure 41 – computeOpTrnDir state chart . 102
IEC CDV 61375-2-3 © IEC 2025
Figure 42 – Use case "sleep mode" state diagram . 104
Figure 43 – Sleep control sequence diagram . 105
Figure 44 – Sleep control function state machine block diagram . 107
Figure 45 – Sleep request protocol sequence chart (example) . 108
Figure 46 – Sleep control state diagram . 108
Figure 47 – Wake-up sequence diagram . 110
Figure 48 – Wake-up function state machine block diagram . 111
Figure 49 – Wake-up state diagram . 112
Figure 50 – Wake-up and Passive Consist Detection circuitry block diagram . 114
Figure 51 – DC voltage appliance directions (example with two active end consist and
one passive middle consist) . 115
Figure 52 – PCD sequence diagram. 116
Figure 53 – PCD control
...