Abstract: The wheel set comprises a pair of load-carrying wheels that run on a track, and that are steerable about parallel axes on a fixed portion, together with two pairs of guide wheels for bearing laterally against the track. The pairs of guide wheels are situated on either side of the load-carrying wheels, and they are carried by the same guide frame which is displaceable relative to the fixed portion only in rotation about a vertical axis. The guide frame is connected to the load-carrying wheels by a forced steering linkage for the load-carrying wheels. The fixed portion is constituted by a transverse box girder placed above the guide frame and provided with steering pivots for the load-carrying wheels, which pivots are placed beneath suspension cushions for the vehicle.

Abstract: For measuring an amount of relative movement between two elements, such as a vehicle and a track, which are mutually movable, two successive pulses of coherent light are directed from the vehicle to the track under a same incidence angle. From a same location of the vehicle, two images of the interference patterns due to the short pulses are formed. The two pulses are offset from each other in the direction of movement by a distance d approximately corresponding to the amount of relative movement between the two pulses. The actual amount of movement is computed as being the movement which provides the best coincidence between the two images. The comparison can be made by cross-correlation.

Abstract: The safety control device with digital input and analog output, is intended to deliver a mean output power above a specified threshold when two binary input sequences which are complementary or in phase opposition are applied to the input and an output power appreciably below the threshold in all other cases. It comprises a primary voltage source (18) supplying a cascade of several modules (16.sub.1 , . . . , 16.sub.k) each having an AC converter bridge and a rectifier, each branch of the AC converter bridge being controlled by one of the sequences.

Abstract: The system comprises an interrogation assembly and a passive responder. One is carried by a mobile and the other by a track. The interrogation assembly includes continuously operating low frequency and medium frequency transmitters. The transmitters have respective antennas directed towards a predetermined zone with respect to the antennas, which is traversed by the responder during movement of the mobile. It further has a unit which is responsive to the characteristics of the responder when the responder is in the zone. The responder has a low frequency reception circuit which controls a medium frequency circuit. Both circuits have radiating circuits which are tuned and the low frequency signal generated in the low frequency circuit is used to short-circuit the medium frequency tuned circuit of the responder, at the rate of low frequency rate.

Abstract: A logic AND circuit comprises, in a cascade arrangement, a threshold oscillator having a power supply input connected to a first circuit input and a clamping amplifier providing an output signal only when simultaneously the voltage on a second circuit input exceeds a threshold and the threshold oscillator delivers an output signal. The oscillator comprises a single transistor whose emitter and collector circuits contain two primary windings of a transformer whose secondary winding constitutes a tuned circuit in association with a four-lead capacitor and whose base is biased from the first input via a filter cell having a parallel-connected four-lead capacitor.

Abstract: An orientable axle with independent wheels comprises a beam perpendicular the axis of the wheels. It also comprises sensors (16, 20) for measuring the position of the beam with respect to the track; a reference position with respect to the track is predetermined. Electromagnets (22) carried by the axle cooperate with the track for exerting on the axle a force for orientating it. A control circuit delivers a current to the electromagnets for moving the axle in an angular direction which tends to cancel out the difference between the measured position and the reference position. The axle can be used on railroad vehicles having to negociate curves at high speeds.

Abstract: A motion measurement device, more particularly designed for measurement of a rotation of a body around an axis. This device comprises a coded wheel drivably connected to said body for rotation and comprising a plurality of holes regularly distributed around said axis. Said holes are binary digits and for one digit is constituted by a simple hole passing through the wheel and, for the other, an open hole connected to the nearest edge of said wheel by a narrow slit. A sensor placed on the path of the holes and comprising two coils facing one another allows determination of the distance travelled by the moving body connected to said coded wheel. The speed and acceleration of the moving body can also be determined.

Abstract: For data communication in the form of messages between railways vehicles moving over a same track, short identical emissions at random times by modulating a directional microwave beam whose angular opening is sufficient in the horizontal direction for maintaining communication in bends of said track and switches and in the vertical direction for maintaining communication during changes in the profile of the track.