This application relates to methods and apparatus for distributed fibre optic sensing and especially to the processing of signals derived from such sensing techniques to characterise events of interest. The application describes a method of distributed fibre optic sensing, comprising; performing distributed fibre optic sensing so as to generate at least one set of measurement signals from each of a plurality of sensing channels of an optical fibre (101) in response to at least one event of interest. For each set of measurement signals, processing the measurement signals from different sensing channels according to an association metric to determine whether any sensing channels are associated with one another and form at least one association matrix indicative of the sensing channels that are associated with one another. The method further comprising performing distributed fibre optic sensing to acquire a further set of measurement signals from said sensing channels in response to a further event of interest and processing said further set of measurement signals based on said at least one association matrix to characterise said further event of interest.

A method and an apparatus for a train control installation are disclosed, and are based on the absolute permissive block concept. The train control installation employs a plurality of generic absolute block signal units (ABSU), wherein each signal unit includes means for detecting the crossing of a train passed a discrete point, means for exchanging data with adjacent ABSUs, means for generating and communicating a movement authority limit to a train, means for generating and displaying a signal indication, and means for enforcing a stop aspect. The train control installation can be used in conjunction with a communication based train control (CBTC) system to provide a degraded mode of operation without impacting the availability and the reliability of the CBTC system. Further, the train control installation has a self-healing feature to maintain train service during an ABSU failure.

A transmitter device for a sensor device detects a magnetic field change caused by an object approaching or moving past the sensor device, in particular by a wheel of a rail vehicle. The transmitter device has at least two alternating-current-fed transmitter oscillating circuits. In order to implement error disclosure of the sensor device in a particularly simple manner, the at least two transmitter oscillating circuits are formed in such a way that the resonance frequencies thereof are different from each other. A sensor device and a method for detecting a magnetic field change are also provided.

A traffic control system (100) includes a railroad crossing control system (10) with a constant warning time device (40), a wheel sensing system (120) with a sensor (122) connected to a rail (20a, 20b) of a railroad track (20) at a predetermined position (P), and a communication network (140) interfacing with the railroad crossing control system (10) and the wheel sensing system (120) and adapted to transmit data. The wheel sensing system (120) provides speed values of a rail vehicle travelling on the railroad track (20), wherein the speed values are transmitted to the railroad crossing control system (10) via the communication network (140) for producing a preemption signal for the traffic signal control system (110). Further, a method for providing a preemption signal for a traffic signal control system (110) is described.

A method is provided for detecting the presence of a rolling stock on a railway track that is subdivided in successive track sections forming successive electrical circuits independently fed with electrical current for monitoring the presence of a rolling stock on a track section. A transmission device for providing electrical current is located at one end of the track section, and a reception device for detecting the electrical current is located at an opposite end of the track section. This method includes steps for continuously feeding the electrical circuit with electrical current and monitoring the presence of a rolling stock on the corresponding track section so that an electrical current can be applied to the electrical circuit if the reception device detects that no rolling stock is present on the track section. A system for detecting presence of a rolling stock on a railway track is also provided.

A system and a method automatically detect whether a vehicle entering a track section of a railway network is shorter than a predefined length. The method includes detecting at a time T0 an entry of the vehicle on a first track subsection. From the time T0, the occupancy states of at least a first subsection and a third subsection are determined in dependence on the time. The occupancy state is either occupied or free. The occupancy states for at least first and third subsections is reported to an evaluation unit at least until the occupancy state of the first subsection is free. The reported occupancy states determined for the at least first and third subsections are processed by the evaluation unit, and from a temporal evolution of the occupancy states of the first and third subsections, it is determined whether the entering vehicle is shorter than the predefined length.

A purpose of the invention is to provide a rail breakage detection device mountable also on a vehicle. The invention is directed to a rail breakage detection device that receives: transmission-device state information indicating whether a rail signal transmission device that sends a rail signal is normal; reception-device state information indicating whether a rail signal reception device that receives a voltage induced by the rail signal is normal; and reception state information indicating whether a voltage induced by the rail signal reception device is received, and the rail breakage detection device performs rail breakage detection on the basis of the transmission-device state information, the reception-device state information, and the reception state information.

A particularly flexible method for automatically calibrating a wheel sensor includes using the wheel sensor to determine that a calibration must be carried out. The wheel sensor determines a point in time suitable for carrying out the calibration and the calibration itself is carried out by the wheel sensor at the determined point in time. A wheel sensor for carrying out the method is also provided.

A particularly flexible method for automatically calibrating a wheel sensor includes using the wheel sensor to determine that a calibration must be carried out. The wheel sensor determines a point in time suitable for carrying out the calibration and the calibration itself is carried out by the wheel sensor at the determined point in time. A wheel sensor for carrying out the method is also provided.

Example implementations relate to receiving vibration notifications from vibration sensors. In example implementations, a subset of a plurality of vibration sensors from which vibration notifications are expected may be identified based on a position of a train along a track. The plurality of vibration sensors may be arranged in a predetermined order on the track. Whether vibration notifications have not been received from consecutive, with respect to the predetermined order, vibration sensors in the subset may be determined.