Originally Posted by whulsey
During that time period and into the Depression many used classics were converted into tow trucks since they usually had large, heavy frames and a fairly powerful engine.
I didn't know that! Interesting! And makes perfect sense. I did a quick search and sure enough, immediately found a Pierce Arrow tow "truck".
Håkan, Hank's Truck Pictures
is a terrific resource for photos of North American trucks of every possible type and age (including modern). The search function is not so convenient, but if you like trucks, you can easily spend a LOT of time browsing there ...