This little dragline requires more than a few hours to get the ' left-brain / right-brain ' sequences going properly in order to remember what lever to push/pull to swing/dig and which foot brake to hold the pull/lift lines at thrr same time.
Not an "RB22" - it's a 22RB (Ruston Bucyrus, aka Rusty Pie-Crust) So it will be a UK-built machine with most likely a Ruston 6YDA diesel engine.
I ran a long-lever one on crane rig in the late 70's/early 80's on a dam construction job. A great tool.
The Ruston Bucyrus quarry stuff we had in the 60's was bigger. 38RB's and 54RB's.
https://en.wikipedia.org/wiki/Ruston-Bucyrus
I used to work for a firm that had a fleet of them, mainly used for digging shafts for tunneling projects. Worked on both the manual controls (which we called Handraulic) and the later air ones. They were "interesting" things to repair and, operating wise, easy to get yourself into trouble if you didn't know what you were doing.