A method for renovating a section of an existing railway line with the removal of a ballast, comprising a first group of steps comprising the steps of: - removing rails, sleepers and ballast of a section of the railway line; - preparing a support layer of said section of the railway line; - positioning a prefabricated foundation module on said support layer; - superposing on said foundation module a prefabricated superstructure plate intended to support one or more rails; characterised in that the first group of steps also comprises the steps of: - positioning a temporary stopper in a corresponding seat of the superstructure plate, said seat being a through hole; the step of positioning the temporary stopper in the corresponding seat of the superstructure plate: • is part of the step of superposing the prefabricated superstructure plate on said foundation module, the insertion of the temporary stopper in said seat taking place as a result of the superposition of the superstructure plate on the foundation module, said stopper being first placed on the foundation module; or • is not part of the step of superposing the prefabricated superstructure plate on said foundation module, the insertion of the temporary stopper into said seat taking place after the step of superposing the superstructure plate on said foundation module; - constraining said temporary stopper to the foundation module for transferring longitudinal and lateral actions due to the passage of rolling stock at reduced speed; - positioning one or more rails on the prefabricated superstructure plate to enable the transit of rolling stock along said section of the railway line; the method comprising a second group of steps comprising the steps of: i)removing said temporary stopper from the seat; ii)creating a bedding layer between the module and the superstructure plate; the step of creating the bedding layer comprising the step of introducing by injection a material intended to fill a space between the foundation module and the superstructure plate; the step of introducing said material by injection also comprises occupying said seat with the material used for the bedding layer, which material by hardening defines a definitive stopper. - removing rails, sleepers and ballast of a section of the railway line; - preparing a support layer of said section of the railway line; - positioning a prefabricated foundation module on said support layer; - superposing on said foundation module a prefabricated superstructure plate intended to support one or more rails; characterised in that the first group of steps also comprises the steps of: - positioning a temporary stopper in a corresponding seat of the superstructure plate, said seat being a through hole; • is part of the step of superposing the prefabricated superstructure plate on said foundation module, the insertion of the temporary stopper in said seat taking place as a result of the superposition of the superstructure plate on the foundation module, said stopper being first placed on the foundation module; or • is not part of the step of superposing the prefabricated superstructure plate on said foundation module, the insertion of the temporary stopper into said seat taking place after the step of superposing the superstructure plate on said foundation module; - constraining said temporary stopper to the foundation module for transferring longitudinal and lateral actions due to the passage of rolling stock at reduced speed; - positioning one or more rails on the prefabricated superstructure plate to enable the transit of rolling stock along said section of the railway line; - constraining said temporary stopper to the foundation module for transferring longitudinal and lateral actions due to the passage of rolling stock at reduced speed; - positioning one or more rails on the prefabricated superstructure plate to enable the transit of rolling stock along said section of the railway line; i)removing said temporary stopper from the seat; ii)creating a bedding layer between the module and the superstructure plate; the step of creating the bedding layer comprising the step of introducing by injection a material intended to fill a space between the foundation module and the superstructure plate; the step of introducing said material by injection also comprises occupying said seat with the material used for the bedding layer, which material by hardening defines a definitive stopper.