I used to work for a custom harvester who also ran some grain trucks. I didn't go on the "run" with him until several years had passed. He had a good crew with several of my friends, and a summer spent working with them sounded pretty cool.
The route ended in Great Falls, MT. We cut for a farmer who had a quite a bit of ground, and who was younger than my friends and I. We had a pretty good time - his "hired man" was his best friend, and he liked to party. Right up our alley.
At any rate, we actually got some wheat cut. I drove "my" truck and hauled wheat from the fields to the elevator in town. One afternoon as I was returning to the field, I happened to catch a rental truck pulling a small sport utility behind it - I think it was a Mitsubishi Montero. It was on one of those little single axle jobs that support one end of a car, while the other axle stays on the ground. At any rate, the Mitsu was leaving a trail of smoke, and the driver of the truck wasn't aware of the problem. We were on a four lane, so I was able to pull beside him, get his attention, and pull over. There was a paved shoulder, so he was pretty well off the road.
It was definitely smoking from under the hood, and there was a thin trail of oil marking the passage of the stricken SUV. As he was pulling over, the little SUV sounded like a dryer rolling a load of nuts and bolts. I walked up to the front of the Montero and met the owner and his wife. More smoke was rolling from under the hood, and we could see fire erupt. The flames were licking past the seam between the hood and fenders. I ran back to my truck and grabbed the fire extinguisher we are required to carry. The owner popped the hood, and I wanted to raise it. He decided - and rightly so - that would be a bad idea. Giving that fire more fresh air might have been disastrous for anyone standing near the front. So, I emptied the extinguisher over the top of the radiator as best I could, but it was to no avail.
About this time, "our" farmer showed up. He was a volunteer fireman, so he knew what to do - I sure as hell didn't. He had the owner pull the unit a bit closer to the road - away from the ditch. If the dried grass caught, the whole country could go up in flames. He then (I thought this took some 'nads, too) unhooked the trailer from the rental truck, and told the gentleman and his wife if there was anything in the SUV they wanted from the back, they'd better get it out now. They did have the cargo hold loaded, so they pulled their belongings from the rear.
It turned out that neither one of them had driven a small truck like that before, nor loaded a car trailer. Apparently, when you rent all this stuff, the agency will put load the towed vehicle on the little trailer and hook it to the box truck.
The Mitsu had a manual transmission.
It was still in first gear.
Now, let us think about this for a minute. First gear might top out at thirty or forty miles an hour, but probably more like twenty five. Top out as "redline." As do not exceed this rpm. The owner, who had no towing experience, would not have any idea his "load" was pulling too hard. He was running about sixty or so when I caught him.
I'd bet that poor motor was being forced to "run" at least twice the redline rpms. Not only did it run above that rate, it ran until things started breaking, and even after that. It ran long enough to get so hot the oil - no doubt released from the block by a shattered rod - caught fire. I'd bet the upper end went out first - the valves going beyond floating, contacting the pistons because they couldn't spring back fast enough. The camshaft would surely break. Pistons with valves hammering on their tops plus the extended high speed run would stress the connecting rods until they broke. After that miasma of metal chunks and shavings was circulating around what was left, the crankshaft would surely break - so at least the cam wasn't forced to turn anymore.
When I left, the front end was engulfed in flames, and smoke filled the passenger compartment. There was nothing more I could do - the fire department was on it's way, and I was just in the way. When I hauled my next load to town, the poor little truckster was completely burned out - no glass, no interior, no tires so the rims were on the ground, and the body shell looked rusted out. The fire department let it burn out and just made sure the fire didn't spread.
I rather expect a certain rental agency ended up buying those travelers a new SUV.