This thesis was conducted at Dellner Couplers Sweden, where the focus is train couplers.Couplers are made to attach train carriages together but also there is a great focus on safety andreducing force of impact integrated in the couplers.The couplers also connect electricity and band width between train carriages. In order toconnect the electrical couplers when docking, air pressure or electrical actuators are used. Themajority of the time air pressure is used to operate a pneumatic cylinder installed behind theelectrical coupler, using a piston rod in order to push it forward.The purpose of the thesis is to relocate the pneumatic cylinder from behind the electricalcoupler, and place it underneath it, reducing the weight and volume as much as possible.Material selection for the pneumatic system will be to identify whether weight can be reduced.Information from Dellner provided the foundation for the concept generation used with, themain metrics being to, produce force up to 3kN and, to handle pressures up to 10bar.In order for the placement to be changed from the back to underneath, changes were made toother parts, such as the frame and the electrical coupler box.Calculations were made on the part, in order to have a basic understanding of whatmeasurements were required.Two concepts were chosen and visualized using Inventor (software). Prototype 4 hade doublecylinder with piston rod. Prototype 6 had a double cylinder but was rod less.In order to make sure the prototypes met all the requirements, both in terms of stress analysisand being able to generate force, they were FEA tested.The material selection was made in order to see how much weight could be lowered withoutlosing the integrity of the prototypes resulting in, a chart made showing the different materialselections for both prototypes.