Abstract: A system and method for providing a virtual approach signal restriction upgrade between physical signaling components is presented. In one embodiment, in a CTC type of operation, the use of a virtual signal with signal type functionality to split a block into two or more sections can allow a train currently governed by an approach indication to accelerate on a clear indication if the advance signal indication upgrades. The addition of audio frequency type circuits with the advance signal indication can allow a train to upgrade from a restricting indication to an approach or clear indication, while protecting open HT switches, broken rail, hazards, and follow up moves. The present invention provides a system for allowing trains to upgrade from a “restricting” indication to an “approach” or “clear and accelerate” indication with an upgraded PTC track line for the segment.

Abstract: A system and method for virtual block operational status control with long block time delay is presented. The present disclosure can advantageously increase the capacity and safety of the existing railroad track infrastructure used by the railroads by determining whether a virtual block is healthy or unhealthy. The long block mode can provide a coarse granularity on the presence of a train. In virtual block mode, the system can implement a finer granularity so the virtual aspects of the sub blocks can be realized. The present disclosure provides a long block mode that can provide the system an opportunity to analyze the potential tradeoffs between granularity and reliability by determining which mode (virtual block or long block) is best utilized in a given situation. The system can operate by default in long block mode and ignore the virtual block capabilities until absolutely needed.