Is there any differential in train?
No. Wheel tread “taper” mitigates to substantial degree the natural bind inherent in traversing a curve when one wheel must spin faster to cover the outside (longer) distance in the absence of a differential. Taper also serves to center the truck on tangent (straight) track, eliminating truck “hunting,” and the detrimental lateral forces created during hunting with the trucks banging back and forth on the lateral plane, with the extreme cases resulting in derailment due to rail climb by the wheel or rail laying over… Curve greasers or flange lubricators are employed as well to cut down on friction and therefore reducing resistance through curvature.
