|Wagner Model H|
In their day (the 1950's and '60's), this 3 wheeled front end loader was intensely popular with state and county road departments, particularly around Oregon where they were made. Some survived for many years after that. Indeed the photos shown here were taken in 2009. The key feature that made the machines so popular was that they were towable. The towbar is missing in the photo, but you can see the base for it on the single wheel. They had a way to disconnect the steering so it could follow the dump truck, and the only other thing you had to do was to remove the 'side bars' anchoring the planetary drives to the fender. Once these were removed the machine would 'free wheel', and could be easily towed behind a dump truck.
While there may have been diesel engine versions, the ones I am familiar with had a Chrysler 6 industrial engine (the same as used in the Dodge pickup including the Dodge powerwagon). It also usually had a Chrysler 'torque coupling'. The 'front' tires were 14x24 tires typical of a roadgrader which limited the towing speed to 25-30 MPH.