About this 3D model

Just wanted to design something sophisticated for my BRIO style Train set with magnets etc... Came to the conclusion, that simple is often the best! So I did a set of couplers made from a simple Hook and a Ring - they do their job as well! 123d File is included so you can adapt to your needs. Just drill a 5mm hole in the baseplate of the train, glue it in and here you go!