Abstract: A frequency generator for generating a working frequency for a transmission signal of a rail contact of an axle counter includes a series resonant circuit having a transmitter coil unit of the rail contact and a capacitor. The frequency generator has an inverter, the output of which is connected to the capacitor. The inverter is configured to generate an oscillating voltage and to feed the generated oscillating voltage to the transmitter coil unit of the rail contact via the capacitor. A current transformer synchronizes the output voltage of the inverter to the current in the series resonant circuit. A start-up circuit electrically connected to the inverter is configured to trigger the inverter and to be electrically connected to an input power supply. The frequency generator is a robust and effective circuit for generation of magnetic fields where manufacturing effort and expensive components can be reduced.

Abstract: A rail contact element for drop off detection is disclosed, wherein the rail contact element is mountable to a rail and includes a spring element, a main body which holds the spring element and an optical fiber. The spring element is in a tension state or in a relax state depending on a mounting state of the rail contact element. The optical fiber includes an outlet surface for emitting a light beam and the rail contact element further includes a reflector element. The spring element, the reflector element and the optical fiber are arranged so that the influence of the reflector element on the light beam is different in the tension state than in the relax state.

Abstract: A method for assembling a strain gauge arrangement for an axle counter, includes: a strain sensor element; a carrier, to which the strain sensor element is fastened; and a railroad track structure to be monitored. When the carrier is fastened to the structure at least a part of it is kept in an elastically deformed state. The carrier is embodied with a first carrier piece opposing a second carrier piece. The strain sensor element is fastened to the first carrier piece with a first fixing point, to the second carrier piece with a second fixing point, and to neither the first nor the second carrier piece with a central section between the fixing points. At least the part of the carrier is elastically braced by means of a bracing element for when adhesively bonding to the structure to be monitored. Thereafter the bracing element is removed.

Abstract: A fiber optic sensor unit for detecting a mechanical force acting on a rail includes at least a first sensor fiber, a first elongated fiber optic strain sensor and a second elongated fiber optic strain sensor. The first sensor fiber includes the first strain sensor and is characterized in that the at least one sensor fiber is attached to a sensor plate. The first fiber strain sensor and the second strain sensor are arranged in an x-type or v-type geometry, wherein the first strain sensor and the second strain sensor are arranged in an angle of 60° to 120°, in particular of 90°, to each other. Measurements with increased amplification of the measurement signal and improved raw data can be made.

Abstract: A method for assembling a strain gauge arrangement for an axle counter, includes: a strain sensor element; a carrier, to which the strain sensor element is fastened; and a railroad track structure to be monitored. When the carrier is fastened to the structure at least a part of it is kept in an elastically deformed state. The carrier is embodied with a first carrier piece opposing a second carrier piece. The strain sensor element is fastened to the first carrier piece with a first fixing point, to the second carrier piece with a second fixing point, and to neither the first nor the second carrier piece with a central section between the fixing points. At least the part of the carrier is elastically braced by means of a bracing element for when adhesively bonding to the structure to be monitored. Thereafter the bracing element is removed.

Abstract: A strain gauge arrangement for an axle counter has a strain sensor element, a carrier and a railway line structure that is to be monitored. At least one part of the carrier is maintained in an elastically deformed state by the structure when the carrier is secured to the structure. The carrier is formed from a first carrier piece and a second carrier piece, which lie opposite one another at a distance from one another. The strain sensor element has one first fixing point fixed to the first carrier piece, and one second fixing point fixed to the second carrier piece, and a middle section mounted between the fixing points which are not fixed to the first or second carrier piece. The strain gauge arrangement is simple to handle and a drop can be reliably detected and a strain state of the strain sensor element can be predetermined more easily.

Abstract: A strain gauge arrangement for an axle counter has a strain sensor element, a carrier and a railway line structure that is to be monitored. At least one part of the carrier is maintained in an elastically deformed state by the structure when the carrier is secured to the structure. The carrier is formed from a first carrier piece and a second carrier piece, which lie opposite one another at a distance from one another. The strain sensor element has one first fixing point fixed to the first carrier piece, and one second fixing point fixed to the second carrier piece, and a middle section mounted between the fixing points which are not fixed to the first or second carrier piece. The strain gauge arrangement is simple to handle and a drop can be reliably detected and a strain state of the strain sensor element can be predetermined more easily.

Abstract: An axle-counting method for railbound vehicles includes the following method steps: coupling light into at least one sensor fiber, wherein the sensor fiber includes at least one fiber Bragg grating mounted on a rail, wherein each fiber Bragg grating has a reflection spectrum having a reflection peak which is at a Bragg wavelength and has a full width at half maximum; generating a difference signal from two shear stress signals through detection and filtering the temporal intensity course of the light power reflected by two Fiber Bragg gratings which are arranged at a separation from one another; and generating a wheel signal if the difference signal exceeds a predetermined shear stress difference limiting value.

Abstract: A method for operating an axle counter system for monitoring the occupation status of a track section being limited by counting positions which have at least one detection point and at least one counting position a set of redundant detection points, includes the steps of: (a) incrementing or decrementing axle counter values in dependence of the moving direction of a passing axle; (b) transmitting the axle counter value to an axle counter evaluator; (c) determining the number of remaining axles within the track section; and (d) outputting a track occupation status. Prior to step (c) for each counting position exactly one detection point is selected for further processing independent of the selection at any other counting position. In step (c) the counter values of the selected detection points are used for determining the number of remaining axles and the counter values of the non-selected redundant detection points are ignored.

Abstract: An axle-counting method for railbound vehicles includes the following method steps: coupling light into at least one sensor fiber, wherein the sensor fiber includes at least one fiber Bragg grating mounted on a rail, wherein each fiber Bragg grating has a reflection spectrum having a reflection peak which is at a Bragg wavelength and has a full width at half maximum; generating a difference signal from two shear stress signals through detection and filtering the temporal intensity course of the light power reflected by two Fiber Bragg gratings which are arranged at a separation from one another; and generating a wheel signal if the difference signal exceeds a predetermined shear stress difference limiting value.

Abstract: A method for operating an axle counter system for monitoring the occupation status of a track section being limited by counting positions which have at least one detection point and at at least one counting position a set of redundant detection points, includes the steps of: (a) incrementing or decrementing axle counter values in dependence of the moving direction of a passing axle; (b) transmitting the axle counter value to an axle counter evaluator; (c) determining the number of remaining axles within the track section; and (d) outputting a track occupation status. Prior to step (c) for each counting position exactly one detection point is selected for further processing independent of the selection at any other counting position. In step (c) the counter values of the selected detection points are used for determining the number of remaining axles and the counter values of the non-selected redundant detection points are ignored.

Abstract: A method and apparatus for determining the occupancy status of a track section, in particular following a restart of an axle counting system, in which a counting-in axle counting point is provided at the start and a counting-out axle counting point is provided at the end of the track section. The occupancy status is determined by a comparison of the counting values currently ascertained by these axle counting points. The current counting value of the counting-in axle counting point and the current counting value of the counting-out axle counting point are stored following clearing of the track section. To determine the new occupancy status later, the values thus stored are called on together with the counting values current at the time.

Abstract: An automatic recirculation non-return valve comprises a check valve located in a main duct and a recirculation valve located in a recirculation duct. The check valve is movable between extreme positions of closing and opening the flow cross-section of the main duct. The recirculation duct forms a branch of the main duct upstream of the check valve. The check valve comprises a rotary shutter and a seat cooperating with each other to define a flow cross-section of the recirculation duct. A transmission mechanism couples the movement of the check valve and that of the shutter. The recirculation valve comprises a pressure-balancing mechanism configured in such a manner that, of the downstream surfaces of the shutter, at least one surface is not involved in sealing and is subjected to a pressure substantially equal to the pressure exerted on the upstream surfaces of the shutter.

Abstract: The invention relates to a method for determining the occupancy status of a track section (A1), in particular following a restart of an axle counting system (AZS), in which a counting-in axle counting point (ZP1) is provided at the start and a counting-out axle counting point (ZP2) at the end of the track section, and the occupancy status being determined by a comparison of the counting values (AKT1, AKT2) currently ascertained by these axle counting points, the current counting value (AKT1) of the counting-in axle counting point (ZP1) and the current counting value (AKT2) of the counting-out axle counting point (ZP2) being stored following clearing of the track section (A1) and that to determine the occupancy status afresh later the values thus stored (EIN1, AUS2) are called on together with the counting values (AKT1, AKT2) current at this time, as well as a counting point (ZP1, ZP2, ZP3) and an evaluation device (AZA) for this.