Abstract: A system of train control uses a quasi-moving block methodology for controlling operation of a plurality of trains from a remote office. The office parses the route information for each train into non-overlapping movement authorities that are issued via a communications network. As each train proceeds, it communicates with the office to automatically roll up its movement authority and release the portion of the movement authority behind the train. The office then extends the movement authority of the subsequent train to reflect the released portion of the movement authority of the leading train. The track can be divided into a series of track circuits to enable detection of broken rail or unexpected occupancy. The office segment can then control operation of trains accordingly if broken rail or unexpected occupancy is detected in the train's movement authority.

Abstract: A method for detecting broken rail and track occupancies measures both the electrical current and voltage on each end of the block of track. This allows a broken rail to be detected even with a shunting axle (occupancy) in the same detection block. The method also provides broken rail detection capability to support modes of operation in which a following train maintains safe spacing from a leading train without the use of track circuit information for train location, allowing for reduced train spacing. The current and voltage measurements are used to make binary decisions, in order to minimize the sensitivity to variations in track impedance characteristics. When combined with train location information, this method also allows for identifying the location of a rail break.

Abstract: A method is provided for detecting broken rail, unintentionally misaligned turnouts, and track occupancy ahead of or behind a railway vehicle traveling on a railroad track. Shunts extend between the rails at intervals along the railroad track. Each shunt has electrical signal transmission characteristics differing from those of adjacent shunts. A test unit on the railway vehicle induces a test signal in a first rail to create a track circuit in which the test signal propagates along the first rail, through at least one of the shunts, returns to the railway vehicle along the second rail, and through the wheels and axle of the railway vehicle. The test signal has electrical properties selected to interact with at least one of the shunts. The received test signal on the second rail is analyzed to identify predetermined conditions concerning the status of the railroad track.

Abstract: A method is provided for detecting broken rail, unintentionally misaligned turnouts, and track occupancy ahead of or behind a railway vehicle traveling on a railroad track. Shunts extend between the rails at intervals along the railroad track. Each shunt has electrical signal transmission characteristics differing from those of adjacent shunts. A test unit on the railway vehicle induces a test signal in a first rail to create a track circuit in which the test signal propagates along the first rail, through at least one of the shunts, returns to the railway vehicle along the second rail, and through the wheels and axle of the railway vehicle. The test signal has electrical properties selected to interact with at least one of the shunts. The received test signal on the second rail is analyzed to identify predetermined conditions concerning the status of the railroad track.