What do you call those dump trucks that pull a trailer which is also a load dumper? Is there a special name for those double-the-fun beasts?
Don’t laugh, but they’re called double dump trucks.
Oddly enough, a tandem dump truck is a singular beast with two rear axles, and is pretty much what most people think of when they hear “dump truck.”
Wikipedia lays out more styles of dump trucks that you probably ever imagined.
The smaller one in the back is often referred to as a ‘pup.’
Yep. To dump the main load, they have to back up the trailer in such a way that it is roughly perpendicular to the main truck. They dump the load, and then pull the hitch through the gravel.
We call them “truck and transfers” around here. They drop the trailer and dump the first load. Then the gate to the main dump is left open and they back over the hitch of the trailer. The trailer’s dump body slides off its wheelbase and into the main dump body, and it’s then dumped. It’s reversed to put the trailer back on its wheels and hitched up and off they go.
It doesn’t take as long as it sounds either.
Well when I worked in construction, one of my jobs was to assist the drivers of these double trucks. they would pull up, park and drop the second trailer. Drive onto the construction site, and dump their load. They would then come back open their tailgate all the way up and back up until the two little projections on the front of the trailer fit into two small recesses on the truck. They would then winch the trailer into the main truck bed. Once this was done, they would go dump the trailer’s load. Then they would come back and put the trailer’s box back onto the trailer, and finally hook up the trailer to the truck and drive away. Look close at this picture and you will notice that the box on the trailer is smaller than the one on the truck, so that it can fit inside.
There are also double bottom dump trucks like this picture but with two smaller trailers.
