I recently bought these over the internet:
No, not gold bullion, but neodymium magnets! These are just 10mm x 3.5mm x 2.5mm, so quite small. However they are incredibly strong - it takes a lot of force to separate them from this cluster. The poles are on the largest faces, conveniently, as you have probably guessed I plan to use them in pairs for uncoupling.
A quick test on the workbench (below) suggest they will be plenty strong enough for this, even when placed outside the rails. In fact I plan on replacing some of the cupboard-catch magnets on Awngate with these placed under the track from below, probably under the rails, spaced apart with steel washers. Experimentation to follow!
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjXxChHxVYqZ58izJtDx1Gzf-B3VaikA9mZP1zCC78mkH8Fi_kD23vDKZwM_R-SpuuEF1tYjV_qnpTj6jhfIuPq6ozlxtEfp4pyprJ6eTu8Nb8zh3RB1gd8a0tDl8cnaSBPTQ-OHM4Ea5o/s400/DSCN2517.JPG)
A quick test on the workbench (below) suggest they will be plenty strong enough for this, even when placed outside the rails. In fact I plan on replacing some of the cupboard-catch magnets on Awngate with these placed under the track from below, probably under the rails, spaced apart with steel washers. Experimentation to follow!