So watching the video from the last log, I noticed one mechanism, which seems perfect for my needs. The velocity is almost constant and so I took the time, made some screenshots and started inkscape. Since today is almost friday, 123d design wasn't able to function the way it supposed and i had to export the imported svg file offline to .stl and get it online again and well.... I got to get back to the files soon. The teeth of my gear aren't right, but I'm going to 3D print it and tweak it anyways. I guess no timing is need but I will probably make a locomotive thingy, too. Hopefully I can print the parts during the next week and come up with a frame until then.