model train G-Lab concept

> The magnetic wheel on a train concept can be easy. Take a disk magnet,
> sandwich it between two iron washers that are slightly larger (to span
> the steel rail), and the iron will concentrate the flux at the gap. This
> assembly will hold quite tightly to the rail, and having two wheels on
> an axle, one per rail, will only increase the stability.
>
> The idea is a good one; you will have excellent metal-to-metal contact
> to provide reliable power.