Abstract: A production line includes a carrier board having a power socket that has a plurality of power lines and a plurality of conductive elements connected to the power lines, respectively; a track having a track body and a pair of track sidewalls; a plurality of electricity-collecting tracks provided on the track body for supplying different power signals; and a plurality of guarding units, each of which has a supporting frame perpendicularly provided on the track body and a covering sheet connected to the supporting frame for covering the electricity-collecting tracks, a plurality of crevices formed between each of the covering sheets; wherein each of the conductive elements has a contact end penetrating and extending into each of the crevices and flexibly contacting each of the corresponding electricity-collecting tracks so as to receive the different power signals and transmit the different power signals to the power lines of the power socket.