Aspects of the disclosed embodiments generally relate to railway track circuits, in particular track circuits with continued distance monitoring and broken rail protection.

A method and apparatus to detect breaks in tracks and/or detect the presence of a vehicle, such as a train, in a monitored section of the track or rail. Embodiments of the present invention measure the change in track inductance associated with a track or rail break. Electrical shunts are connected between the rails at spaced-apart intervals (for example a shunt can be placed every mile). At least two different frequencies of alternating current are generated and fed into the segments of rail (for example at or near a mid-point between the shunts). If a rail break occurs, the total inductance of the rail at that segment will change. Using two or more frequencies allows a rail break to be differentiated from environmental rail-to-rail and rail-to-earth leakage.

A grade crossing control system includes a controller that receives start and end inputs corresponding to a train traversing an outer approach, determines the difference in time between the start and end inputs, and uses the difference in time to determine a delay period by which activation of a grade crossing warning system will be delayed following detection of the train by a track occupancy circuit in an inner approach in order to compensate for slow moving trains. The start and end inputs for the outer approach may be supplied in different ways including a separate track occupancy circuit for the outer approach, by train detection devices unconnected to the track at the start and end of the outer approach, or by overlapping track occupancy circuits positioned at the start of the outer and inner approaches.

To locate a shunt, the shunt includes an RF transmitter configured to wirelessly transmit an identifier of the shunt such as the configured shunt frequency. The shunt may include switches or memory locations that may be configured by an installer to correspond to the configured shunt frequency. Other embodiments employ switches or sensors influenced by jumpers installed in the shunt to configure the frequency of the shunt. A portable device receives a transmission including the identifier and displays it along with an indication of the received signal strength of the transmission, and maintenance personnel move the portable device along the track to locate the highest received signal strength, which indicates the location of the shunt. The shunt may also include a test circuit that may be configurable to generate a test frequency, determine a parameter indicative of shunt performance, and output a signal based on the parameter.

The rail fracture detection device detects a rail fracture in a section provided with the track circuit by determining presence or absence of a rail fracture and determining presence or absence of a train on a rail by using information on whether a relay of the track circuit is activated or deactivated and information on a current value of current flowing in the track circuit.

A Wireless Slide Fence utilizing signal reflection technology to detect rockslides and can determine the size and location of fallen rocks/objects impeding travel along a train track is presented. The present disclosure solves the technological problem of determining rock size and location to validate rockslide/fall alarms to reduce false alarms, while minimizing repairs required by conventional systems through the use of obstacle detection units and vital logic controllers. The present disclosure improves the performance of the system by, generating validated alarms when fallen rocks/objects satisfy the size criteria and are located in an area hazardous to train operations. In one exemplary embodiment, a loitering time can be implemented to validate object detections to reduce false positives due to transient objects such as migrating animals.

Aspects of the disclosed embodiments generally relate to railway track circuits, in particular track circuits with continued distance monitoring and broken rail protection.

A system for detecting the presence of a train on a railway track (1b) comprising a plurality of sections (2a, 2b, . . . , 2n), the system comprising: a transmitter (10b) arranged to emit a main signal towards the plurality of sections (2a, 2b, . . . , 2n); a plurality of selecting devices (14a, 14b, . . . , 14n) associated respectively to the plurality of sections (2a, 2b, . . . , 2n) along the railway track (1b) and arranged to selectively allow passage of said main signal towards respective sections of said plurality of sections (2a, 2b, . . . , 2n); a receiver (12b) arranged to receive the main signal after having passed through the plurality of sections (2a, 2b, . . . , 2n); a control unit (20) associated to said receiver (12b) arranged to perform an analysis of said received signal so as to detect the presence of a train on a predetermined section (2a, 2b, . . . , 2n) of said plurality of sections (2a, 2b, 2n).

System, method and portable device for analyzing signals travelling along track circuits of railway lines, wherein at least one antenna captures, in a contactless manner, a plurality of signals travelling along a track circuit, and a demodulator is adapted to separate into individual signals the plurality of signals captured by the antenna and selectively demodulate one or more of the captured signals. An interface is adapted for transferring, to a user interface, data indicative of the demodulated signals. Each demodulated signal is displayed on a screen for a user to trigger any needed corrective action.

A method and system for health assessment of a track circuit and/or of a track section, the track circuit being configured for detecting the presence of a vehicle on the track section between a transmitting end and a receiving end of the track circuit. The method, implemented by an electronic device, comprises obtaining, from a sensor device placed near the receiving end, samples of an electrical parameter of an electric signal transmitted between the transmitting end and the receiving end of the track section, forming a temporal series of received samples, applying an automatic clustering algorithm to separate the received samples in a predetermined number of clusters, selecting one of the clusters and determining, for the selected cluster, a first peak value of the received samples classified within the selected cluster, and calculating a track circuit health indicator depending on the first peak value determined for the selected cluster.