How can this be possible ?
Well, in the first place this has nothing to do with the Marinov-Nikolayev Siberian Coliu, as I explained further down in that thread. In the second place, the diagram is wrong. Each "car" in the train is made in the same way, and one can string together many cars, not contacting except through their fields. The "key" is proper use of spacers between the flat magnets. The system works because of mutual attraction and repulsion zones of the magnets concerned, so that there is an energetic MPE minimum that is not actually in contact with the magnets. The system is unstable though, and with the train of flat magnets and little "cars" it needs to be on a surface so that the cars can't flip over and snap into contact.
I call this system the "Nikolayev trailer hitch" or sometimes other names. I made a whole string of little cars back in the ISSO days in San Francisco, sadly lost by now. The right orientation of the magnets and spacers appears in Nikolayev's Russian book, along with a lot of other interesting things.... none of which violate conventional physics understanding, and most of which don't work in the way Nikolayev tries to claim they do.
Here's a simple version of the basic phenomenon that anyone can do at home with the proper ring and bar magnets. This system relies on the tube to keep the bar magnet from flipping over, but I think it would also work with spin-stabilization and proper counterweighting:http://www.youtube.com/watch?v=nUihboGkJnE
(from August 2011)http://www.youtube.com/watch?v=C69a28Jpmec
(from August 2012)
"The easiest person to fool is yourself" -- Richard Feynman