I’ll add to this:
Modern trailers are up to 53’, scrap haulers use anything 40’ and up. Spread axle trailers are rare in scrap hauling (at least around where I live), because the non-spreads can be had for less money. Not only that, but frequent u-turning a spread axle will end up with chewed up tires. A modern tractor trailer will measure anywhere from 55-70 feet, can be turned around in as little as the length of the trailer + maybe 5 feet, but will need extra room for the tractor to swing around to back straight. The terminal where I work has 110’ from dock bumper to fence, and we run all 53’ trailers.
53 foot trailers were not legal until the early 90’s (forget the exact year), 48 footers were the mid-80’s, 45 footers were mid 70’s, 40 footers were early 60’s, 32-35 footers were mid 50’s, 28 footers were late 40’s, double 28 footers were, uhhh, not exactly sure, early 70’s maybe, and 20 footers (trailers, NOT containers) were late 20’s, early 30’s. For flatbedders, both 48 and 53 foot trailers are very common, but van and reefer trailers are generally 28 and 53 feet only (except by special order, and usually at extra cost.) The reason for the 48 foot flats still being so common is that you can allow the load to overhang, and some states have restrictions on 53 footers, higher tolls, and you have a wider, longer turning radius on one.
I modeled one scrapyard using old brass rail for fence “posts”, aluminum foil shaped like old roofing tin for the “fence siding”, and used all sorts of model railroading scraps for the “junk”.
My local scrapyard is a fairly busy place, and they can afford some newer, more modern equipment. They have a forklift with “rotary forks”, used for picking up and inverting items, they have a Bobcat (an old articulated, center pivot model) with forks and grapple bucket, an old Cat D5 tracked front end loader with clamshell bucket, 3 or 4 large tracked cranes, 1 or 2 with electromagnets, the others with grappl