I recall reading in one of Signor's books a reference to Espee Moguls as being called " A Valley Mallet" ( pronounced maal-EE in true RR fashion). The name referred to the fact that they could pull the same tonnage train down the San Joaquin Valley, that a cab forward ( i.e.-maal-EE )could haul over Donner or Tehachapi. Of course there are several errors contained above; virtually all cab forwards were, I believe, ' simple ' articulateds that did not use the same steam twice, and virtually all Espee freights required helpers ' over the hill'. Still, it shows the respect Espee Engineers showed these locomotives.
Question: Didn't the light axle loadings of the Mogul also contribute to their longevity, for use on light rail branch lines ??? The Friant branch & Sunset Railway come to mind.