Abstract: Method for the aluminothermic welding of rails, involving the steps of: —triggering an aluminothermic reaction in a crucible, —pouring the metal resulting from said reaction into the mold so as to fill the molding cavity from the rail flange, —after filling the cavity, triggering a second aluminothermic reaction above the rail head, and pouring the metal resulting from said reaction into the cavity in the region of the rail head. The mold used in the method is designed to fit over the ends of two rails to form a molding cavity comprising a crucible positioned above the rail head region so that it can be fed with molten metal of the cavity via a secondary passage.

Abstract: The method for evaluating the compactness of a layer of railroad ballast near a railroad tie includes at least one step of taking at least two measurements (11,11a,11b) of the penetration resistance (Qd) of the ballast (13) near one and the same railroad tie (10), and a step of calculating the mean value (Qdmean) of these measurements (11,11a,11b) of penetration resistance (Qd). Also provided are a device for implementing such a method and a method for predicting the settlement of the ballast of a railroad track including a step of evaluating the compactness of a ballast near a railroad tie.