On the final step of our course before heading off to work. Learning to tow 8 ton trailers (the trailer can carry a payload of 8 tons, the trailer itself doesn't weigh that much). Pulling it forward is easy, it just follows the truck. It's reversing that's hard.
Since they have an axle right down the back and another one on a turn table right up the front, you end up with two points of articulation.
The easiest way to think about it, is if you imagine towing a trailer behind your car - then a second trailer behind the first one.
Pulling forward is easy, like a train, both will follow. But reversing? Then it wants to snake and go every which way. Yes, it is possible to crash into your own trailer.
No point doing something easy - you have to challwnge yourself to become better.