Streamlining Your Network Operations by Consolidating the Radio Codeline Over the PTC Network

CTC (Centralized Traffic Control) which is currently based on a very narrow licensed 900 MHz radio band is about to be abandoned because of the FCC modifying the 900 MHz band allocations. Radio hardware manufacturers are ending the production of the radios and will soon discontinue the support for these radios. FCC promised the band transition without the disruption for the railway service, and we have yet to see how this will be executed. Rail industry cannot just sit and wait, however. Seeing the growing trend of using 220 MHz PTC (Positive Train Control) data communication infrastructure as an infrastructure for the future CTC messaging and based on its expertise in network communications and intimate knowledge of PTC, LILEE Systems developed the first complete solution for CTC-over-ITCM (Interoperable Train Control Messaging).

CTC-over-ITCM Technology

LILEE supports CTC-over-ITCM technology through a software module installed on LILEE’s STS-1000 family of Wayside Messaging Servers (WMS). This software module – known as an “FG” or Field Gateway – acts as a “protocol converter” for standardizing messages in the field into the EMP (edge messaging protocol) format that can be distributed to the office. Through the various serial and Ethernet ports available on the STS, existing field logic controllers can interface with the STS using native protocols and converted to an EMP message by the Field Gateway software module before being transmitted to the office.

In the back office, these EMP messages which include CTC data are retrieved from one of the queues on the ITCM and distributed to a COG (Consolidated Office Gateway). The COG converts this CTC message formatted in EMP into its original format. In this manner, the existing dispatch system can continue to use existing protocols to receive indications information from the field. For messages originating from the dispatching system (such as controls), the process is simply reversed. Controls from the dispatching system are converted into the EMP format by the COG and sent to the STS in the field. The FG software in the STS converts the message back to the native protocol used by the logic controllers.

The COG is designed to operate in a clustered high availability configuration to retain the same level of reliability as other systems which utilize the ITCM. The COG is also enabled to provide systems management information to the various systems management applications used by the rail operators. This enables users to access, monitor, and report information such as:

  • Control message payload and tracing
  • Indication message payload and tracing
  • Control point status (online / offline)
  • Path status (220 MHz / cell)
  • Error codes

Why CTC-over-ITCM

Rail operators migrating their CTC communications to the ITCM infrastructure can recognize many operational efficiencies through this standardization, including:

  • An increase in reliability of the overall dispatching system as the ITCM is designed to be highly reliable and available
  • A return on investment in the deployment costs associated with deployment of the PTC communications network
  • Reduction of costly infrastructure required to support ATCS data radio networks
  • Standardization of diagnostics and maintenance, as maintaining a separate knowledge base of legacy protocols is no longer required


Currently there is another implementation of CTC-over-ITCM available, yet it only supports messaging conversion and delivery and lacks the management framework. A good management framework is essential for diagnosing network issues, support of fast-growing network, finding security threats, upgrading network and for identifying the trends to plan for future. The LILEE solution for CTC-over-ITCM includes a comprehensive management framework on top of protocol translation, giving customers full visibility into how the network operates, and based on the observed trends, customers can proactively avoid issues in the future.

Schedule a call with LILEE’s rail technology expert Yale Lee at to discuss implementing the CTC-over-ITCM technology for your rail communications.

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About the Author

Yale Lee
Yale Lee is the Co-founder and Vice President of Technology at LILEE Systems. He has over twenty years of product development experience in the networking and security industry. Yale has led the LILEE engineering and professional services teams to develop and deliver wireless communications solutions to North American Class I railroads to meet Positive Train Control (PTC) requirements.
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