I came across a custom item on eBay and thought that's a good idea

The one I saw was based on three parts, which is the same length as the truck version 3180, and had lots of other nice detailing. I felt that this was a little long, so made a more basic version with only 2 sections. I was quite happy with the result and the basic nature keeps the cost down to make multiple versions, as you can see from the pic below.

I built a total of 5, although eagle-eyed readers may only spot 4 in the photo - the train was too long to fit in my tent...
I also wanted to build the truck with just two bogies and initally tried a design with a small turntable mounted between the bogie and base. However, when I ran it along the track they twisted and derailed the wagon, so I reverted to fixed bogies and Robert is your father's brother...
Is this a trait of single bogie design, as I notice that the bigger trains/wagons have a double bogie arrangement, or is it to do with the overall length of the item...?























