A method for assembling at least one rolling support and guide element with a complementary part by direct flash welding includes the step of a first step carried out by a first flashing phase intended to increase the temperature of the surfaces to be welded in a homogeneous manner, the duration of this first step being between 15 s and 40 s. A second step is carried out by a phase of preheating by Joule effect of the parts to be welded, the duration of this second step being between 45 s and 55 s with a heating current of between 55 kA and 70 kA. A third step is carried out by a second flashing phase to deoxidize the faces to be welded while avoiding their re-oxidation, the duration of this third step being between 12 s and 22 s and with a flashing current of between 16 kA and 19 kA. A step is included bringing the surfaces to be welded into contact.

A method for assembling at least one rolling support and guide element with a complementary part by direct flash welding includes the step of a first step carried out by a first flashing phase intended to increase the temperature of the surfaces to be welded in a homogeneous manner, the duration of this first step being between 15 s and 40 s. A second step is carried out by a phase of preheating by Joule effect of the parts to be welded, the duration of this second step being between 45 s and 55 s with a heating current of between 55 kA and 70 kA. A third step is carried out by a second flashing phase to deoxidize the faces to be welded while avoiding their re-oxidation, the duration of this third step being between 12 s and 22 s and with a flashing current of between 16 kA and 19 kA. A step is included bringing the surfaces to be welded into contact.

A welding unit for welding rails of a track includes a first sub-unit which is displaceable on unit guides in a rail longitudinal direction relative to a second sub-unit by using displacement cylinders. Each sub-unit includes clamping cylinders disposed underneath the unit guides and coupled to clamping jaws for clamping the rails. The two sub-units are connected by the displacement cylinders in that a cylinder body of the respective displacement cylinder is connected to one sub-unit and a piston rod of the respective displacement cylinder is connected to the other sub-unit. Thus, it is not necessary to support the displacement cylinders relative to a transverse beam disposed at the front.

A welding unit for welding rails of a track includes a first sub-unit which is displaceable on unit guides in a rail longitudinal direction relative to a second sub-unit by using displacement cylinders. Each sub-unit includes clamping cylinders disposed underneath the unit guides and coupled to clamping jaws for clamping the rails. The two sub-units are connected by the displacement cylinders in that a cylinder body of the respective displacement cylinder is connected to one sub-unit and a piston rod of the respective displacement cylinder is connected to the other sub-unit. Thus, it is not necessary to support the displacement cylinders relative to a transverse beam disposed at the front.