Table of contents
Overview
Interoperable Train Control Messaging (ITCM) is a messaging system used by the railroad industry. The Centralized train control (CTC) messages are transported over ITCM. A railroad edge messaging protocol (EMP) header and a railroad Class D messaging transport header are appended to the message to generate a packet. The packet is transmitted to a receiving one of the railroad dispatch system and the railroad wayside system across the railroad communications system.
Basic Message Packet Structure
ITCM is appeneded as part of EMP message body. Refer to Class D for additional details
PTC Message Type (EMP Message Type)
Wayside Interface Unit (WIU)
Reference: AAR S‐9202 - Interoperable Train Control Wayside Interface Unit Requirements Railway Electronics
| Message Type | hex | decimal |
|---|---|---|
| WIUStatus Timed Beacon | 13 EC | 5100 |
| GetWIUStatus Response | 13 ED | 5101 |
| GetWIUStatus | 14 51 | 5201 |
| BeaconOn | 14 50 | 5200 |
| Time | 14 B4 | 5300 |
Wayside Device Controller (WDC)
Reference: US-10160466B1, US-2019126961
| Message Type | hex | decimal |
|---|---|---|
| WDC Status | 1B D0 | 7120 |
| WDC Status Ack | 1B D1 | 7121 |
| WDC Status Nack | 1B D2 | 7122 |
| Get WDC Status | 1B D3 | 7123 |
| WDC Control | 1B D4 | 7124 |
| WDC Control Ack | 1B D5 | 7125 |
| WDC Control Nack | 1B D6 | 7126 |
| WDC Reset Sequence Number | 1B D7 | 7127 |
| WDC Reset Sequence Number Ack | 1B D8 | 7128 |
Automated Train Operation (ATO)
Reference: Automated Train Operation Interface Requirements Specification Development Summary Report
| Message Type | hex | decimal |
|---|---|---|
| ITC-ATO Ex to ITC-ATOSS BO Poll | 00 64 | 100 |
| ITC-ATOSS BO to ITC-ATO Ex Poll ACK | 00 65 | 101 |
| ITC-ATOSS BO Poll Registration | 00 66 | 102 |
| ITC-ATO Ex/ITC-ATO SP Configuration Version List Request | 00 67 | 103 |
| ITC-ATO Ex System State Report | 00 6E | 110 |
| Exception Report | 00 6F | 111 |
| Information Request ACK | 00 72 | 114 |
| Information Retrieval | 00 73 | 115 |
| Condition Resolution ACK | 00 74 | 116 |