About this 3D model

I wanted to give my son a NYC subway train to use with his other wooden trains but I felt the one being sold was too expensive. So I designed my own version of an NYC train compatible with other wood and magnet trains.I designed it to have the same functionality of connecting that the new Thomas trains have, that they can connect in any orientation.The magnets used are 5-6mm magnet balls.The subway car and bottom are separate so that anyone or myself in the future could design a new top.