Looks like a Tesmec-built rig. This company specialises in building large crawler trenchers and another similar machine called a "rock saw", although to be honest, I'm not all too sure what the difference is?
I've never seen any in person, but even in pictures they are behemoths, it'd be nice to see them at work for sure! I know a woman who lives in Odessa (Texas), had two of these Tesmec rigs working some distance behind her house. They have thick rock beds there and the machines were being used to cut trenches into it, apparently the dust cloud could be seen for miles!!
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Well for some reason I couldn't post another topic covering trenchers, so here's one from today's wanderings just after purchasing a new lens for my camera.
Its certainly not in the same league as the above (possible Tesmec) trencher but since I've never managed to get pictures of one of these before, its something different for me to wander about and annoy people with.
If anyone's wondering, the black stick to the left on the first picture is my monopod which I use with the heavier lens. The last picture contains the only number of any sort which I could see on the machine, apart from an engine part being labelled
Ford. The number on the plate is
CKA 6958. A parts number perhaps? Ok so the engine is Ford, but what about the machine on which the trencher is mounted, a Ford conversion perhaps, or just Ford powered?