I have driven all sizes of HGV vehicles and also had a plant operators 'card' for driving dump trucks of all sizes (artic' 6x6 ones and 4x4 up to 200 ton or more), Back hoes (excavators) and Front Loaders.
HGVs not much fun in today's traffic, and pay is rubbish for the skills involved.
Big dump trucks are nice, but lots of greasing before starting work. Scary at first, especially when tipping a load over a 100ft drop. Everyone gets out of your way.
Excavators need lots of practice and skill. Biggest I've driven weighed 60 tons, you could fit a kingsize bed or 4 tons in the bucket and could reach down and dig you a hole nearly 30ft deep.
This is the actual one...
Front loaders not too bad...got to be quick and accurate. They articulate in the middle, so can work fast in tight spaces.
This is like the one I used to drive...30 tons weight. Good for shifting stuff.
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My friend drove dozers and graders, as well as the vehicles I drove, and he reckoned those two were the most difficult to master.