A method including measuring a distance between two successive supporting poles delimiting a section to be realized, inputting data into a computer programmed to output a layout plan indicating a position and a length for each dropper to install, preparing each dropper with a dedicated machine, moving a first platform along the section, which is equipped with a position unit and a marking device to set a mark on the contact wire at each position where a dropper is to installed, moving a second platform along the section, the second platform being loaded with the droppers that have been prepared, and fixing manually each dropper between the messenger wire and the contact wire in registration with a corresponding mark set on the contact wire.