You'd be amazed what this car picks up on a trip around the layout. The Neodymium magnet has a pull force of over 100 pounds, it's the K&J BY0X08-N52.
Everything but the axles and that coupler screw is non-magnetic, I use plastic wheels as the friction with the magnetic attraction stopped the metal wheels cold and it was just dragging them down the track. When done, I just pick the magnet out of the car and all the stuff falls off the bottom of the car.