Crane with a thumb?

[6011Artist]

In the early 90's the first one I saw was called a "Zack Built". I thought that he designed it himself, not sure of that but that was my impression. Now you see them everywhere used for heavy towing. He designed and built his to do railcar recovery work. A train derails and he can pick it up and put it back on the track. The boom is usually short and most people never realize it can extend out like that. The thumb looking things are actually the wheel lift. In the photo, it looks like they are placing the cab on an old railroad engine.