Technically, a "Camelback" locomotive is of the Winnan's design and has the cab completely above the boiler. The name is derived because the crew were riding above the engine in a manner like a person riding a camel. A true camel rider does not straddle the camel like a horseman, but rather sits either cross legged behind the hump (or between them on the double-hump variety) or with their legs extened forward with the feet along side of or nearly around the camels neck.
Most of the photos here are of engines that should technically be called "Mother Hubbard"s. It is only relatively recently (since the Diesel era started) that they became known as Camelbacks. A Mother Hubbard has the cab straddling the boiler and the engineer sits at about the level of the foot board on most other locomotives.
The only question I have about these that I have been trying to find out for several years is why the name Mother Hubbard was given to the design. None of the versions of the Old Mother Hubbard poems that I have come across have given any clue.
Anybody have any ideas about the why of the name or where it came from?