Dumb question: what's a "field follow?"

Anyone have any info on when the 657G will become a "K"? Why has the 637G taken so long to be updated in comparison to all other machines such as excavators and loaders for example?

I'm not a dirt guy, but I think it refers to a prototype of a new version of a machine, which the manufacturer puts into regular service in the field, for testing and evaluation. I could be wrong.

The "field follow" definition is basically correct. After designing and testing machines at their proving grounds with their employees operating, Cat builds a number of machines of each product which are then given to selected customers to operate along side of their machines of the same family. This process is monitored by Cat engineering. Upon completion based upon the outcome and customer acceptance, the machine is released for production.

Over the last few years, Cat has had to redesign every machine in their product line to meet emissions standards and then house the required filters and tanks. Yes it appears that they concentrated on high volume machines and families first - bulldozers, excavators, rubber tired loaders and articulated dump trucks. Likewise the smaller graders; 120, 12 and 140: have been done. I've yet to find an updated 14, 16 or 24. There is a new 18. Only one of the track loaders has been updated, 963. Two remain at the lower EPA tier. The 620 family of pans was done. Now you are seeing the action on the 630 family. The 657 is now largely a mining machine and mining is very slow.