And this is how Mercedes-Benz was testing components for the new Actros SLT series. I took these photo’s about two years ago during a visit to Germany.
Take a look at the first trailer, it has four axles. Behind it another 3- axled trailer and as you can see on the lower photo even with an extra drawbar! Probably this combination was used testing the VIAB turboclutch that is available in the new SLT trucks.