Public transport vehicles require cyclic loading in their mechanical systems, which generally leads to the implementation of short-term maintenance plans and compels their manufacturers or owners to pay high monetary costs. One of these systems is the door opening and closing mechanism. High forces tend to be applied 3356 Héctor F. Quintero et al. for this mechanism, causing problems in its components and, hence, malfunction in a shorter period of time. This paper shows the redesign of a door opening and closing mechanism in which an optimization process is implemented based on genetic algorithms; the objective variable being the improvement of the mechanism's transmission angle. In this document, a comparative kinetostatic analysis of both the original and the redesigned mechanisms is carried out through a multi-body dynamics simulation. The results found in the simulation point out that the reactions of the proposed mechanism are reduced. In the experimental part of this work, a prototype of the designed mechanism was built and subjected to cyclic closing and opening operations. The results of this practice confirmed the advantages of the designed mechanism.