PTC Development

Since 2001, the efforts to deploy PTC on various railroads have accelerated. These deployments were mostly started with development specific to the territory and the type of service the system would be installed to operate on (e.g., passenger service). These systems also vary in their implementations of the basic functionalities of a PTC system (i.e. to enforce authority and speed, as well as to protect roadway workers). Even the design of each system tends to be unique. Some systems use track transponders, mainly on passenger lines, to track trains. Others use GPS, supplemented by onboard devices for tracking. A few systems employ a centralized office system to perform major safety-critical functions, but others choose local distributed systems with peer-to-peer communication between a train and the wayside interface units. Some railroads elected to develop vital systems with safety-critical and fail-safe implementation. Others started with a non-vital overlay system where the protection relies mainly on the base system with an additional layer of protection from the PTC overlay. When the PTC overlay fails, the system is protected by the original base system. Generally, the non-vital overlay systems are less expensive to deploy.

The table below lists the various PTC systems that have been deployed or are under development and test, as of January 2007.

 FRA provided funding and technical supports for system development of ETMS, ITCS, CAS, and NAJPTC.   In addition, in cooperation with the industry and the AAR committees, FRA has supported the following PTC-related projects. 

• Universal Onboard Platform
• Higher Performance Digital Radio
• Communication Management Units
• Software Defined Radio
• TTCI Communication and PTC Test Beds
• Hi-Speed Wireless Data Transmission with 802.11x Protocol
• Employee-in-Charge Portable Terminals
• Risk Assessment Modeling