it actually is rather scale......
http://www.cat.com/cda/layout?m=383895&x=7
Main System – Maximum Flow (Total) 232 gal/min
880 L/minSwing System – Maximum Flow 95 gal/min
Maximum Pressure – Equipment – Normal 5076 psi
35000 kPaMaximum Pressure – Travel 5076 psi
35000 kPaMaximum Pressure – Swing 4264 psi
we use 1 pump for everything (or in the usual case, electric motors)
if we scale that psi down to scale, say 1/14.5 that would mean
350psi main which is kinda in the league of vario. a cat 320 has the same pressure as a 374.. the flow varies.
however the flow should be 16 gallons a minute.. and it flows at what rate? around a litre! that's the part that isn't scale. because flow = big gears = resistance = power = big motors and big power drain.
now the other big thing is weight:
back to the 374 - Operating Weight 156819
in scale weight = 10815lbs
although my weight calculations could be wrong. not sure if scale weight is calculated any different than linear size
now keep in mind that models are made out of aluminum. if dense carbon steel is used, weight could easily be doubled or tripled. but that is a whole other mess on its own using steel