A stevedore loads and unloads ships. In other places they are just called dockers.
abdi
a dock man or a longshoreman
Depending on the context it could be a delivery man, wharehouse man, loader, Quartermaster.
stevedore
Stevedore is the place where the ships are (un)loaded , the people are called Longshoremen or Dockmen.
Trucks for performing haulage--which is supposed to mean any kind of commercial transport but usually means carrying gravel, garbage and other such loads. In the US we call these vocational trucks. A heavy haulage truck, which is also known as a fifth wheel trucking system or ballast truck, is a vehicle designed to handle much larger equipment and haulage loads than your standard semi or tractor trailer.
A fleet of trucks is called a convoy.
convoy
A row of semi trucks. There isn't a specific name for it.
A hive
Sales on tow trucks aren't very common, but a person could start by looking locally at any towing companies. If there any towing companies in the area, someone could call or visit them to see if they're selling any repo tow trucks, and if they're not, proceed to ask if they know of any that are for sale.