have tubular sections which may or may not be articulated these tubular sections may also be disposed at a distance one from the other each one comprising a heating unit and are preferably connected to each other by coverings or sleeves to retain the heat fig1 to 13 show placed one after the other a third embodiment of a train for substitution completed in front of the heating vehicle 1 by a welding vehicle 80 to weld the new rails r2 before the latter are neutralised furthermore the heating tunnels of the vehicle 1 are shorter and are installed lower down such that the path of the rails r2 is located below the axles of the bogies at a distance of between 20 to 40 cm preferably between 25 and 30 cm from the ballast by virtue of this disposition there is no need to lift the rails very high and especially above the axles which facilitates the work and the guiding of the rails the parts of the heating vehicle 1 which correspond to the parts of the first example have the same reference symbols vehicle 1 fig1 supplied with a leading bogie 5 and with a rear bogie 12 runs on the old rails r1 and comprises a body 4 comprising a cabin 4a compartments 4b for inverters which supply power.