That's right, I'm talking about prime movers for semi-trailers.
One of the things Australians who are paying attention will notice in Europe is that there is not a long nosed prime mover to be seen. They are all flat faced (I believe the technical term is something like 'cabin over engine').
Road train on the Newell Highway, New South Wales.
Why is this so, and why do long noses dominate in Australia? I went digging on the internet to find out.
The short answer is space. Flat faced trucks take up less space and are more manoeuverable, so in Europe they are more practical. Whereas in Australia the environmental factor that trucks struggle with the most is dust, and long nosed (technical term 'bonneted') are easier to maintain. They also allow for a more powerful engine.
Road train on the outskirts of Goondiwindi.
The long answer involves regulations that specify different axle configurations and load weights in different regions and is too complicated to go into. But if you are interested, I suggest you read this article: https://historicvehicles.com.au/working-vehicles/why-australian-heavy-trucks-are-the-way-they-are/
In the course of my reading on this subject I also discovered that the term 'B-double' is only used in Australia, and that any multi-trailered rig is a roadtrain. I had thought there must be some technical difference between a B-double and a roadtrain, but the reason we have two names for the same thing turns out to be political. When roadtrains were allowed into the more populated areas of Australia, the politician in charge of the change thought the public would be scared of having roadtrains in their home towns so he coined the term 'B-double'.