Abstract: Coating for conferring good friction properties upon a substrate and comprising a non-equilibrium alloy of chromium and nitrogen. The alloy comprises, per one hundred atoms, from 87 to 68 atoms of chromium and from 13 to 32 atoms of nitrogen and two phases, a cubic microcrystalline chromium phase containing included nitrogen and a quadratic chromium nitride phase with a stoichiometric deficient nitrogen content relative to the Cr.sub.2 N nitride. The ratio of the quadratic nitride lattice parameters is between 1.02 and 1.5. This quadratic nitride was previously unknown and probably can exist only in association with chromium. It resists wear up to five times better than known single-phase chromium-nitrogen alloys and is free of the inherent fragility of two-phase alloys containing hexagonal Cr.sub.2 N nitride. The coatings are obtained by magnetron cathode sputtering of chromium with a nitrogen partial presure in a rare gas atmosphere between a maximum and a minimum determined experimentally.

Abstract: A device (1) for adjusting the bearing force of a pantograph (30) of a railroad train set (10) on a catenary wire (2). The pantograph (30) has, at its upper end, a bow (3) in mechanical and electrical contact with the catenary wire (2), connected mechanically to an actuator (7, 34) exerting a nominal force on it at predetermined points and in a predetermined direction. A device (31) measures the contact force between the bow (3) of the pantograph (300 and the catenary wire (2) supplies information relating to the measured force. A transmitter (5, 4a) transmits the measurement information from the measuring device (31, 40) into an appropriate zone of the railroad train set (10). A processor (60, 20) processes the transmitted information and set-point range signals and supplies logical control signals. The actuator (6, 7) is controlled from the logical control signals when the measured contact force exceeds a predetermined maximum force threshold (Smax) or in responses to predetermined external control signals.

Abstract: Pneumatic device for applying the upper end of a pantograph, termed a horned slipper holder, against the overhead contact wire with an appropriate pressure, characterized in that the pneumatic cushion (4) has, inside the leaktight enclosure (28) which is formed by the two cover plates (21, 22) and the rubber bellows (23), a connecting rod (32) exerting on the movable cover plate (22) a translational displacement which is reproducible as a function of the air pressure prevailing in the enclosure (28). This translational movement is transformed, via the two arms (34) acting on two ropes (38) and on two cams (39), into a rotation of the shaft (7) of the lower arm (8) of the pantograph.